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First Time Set-Up - 1
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Introduction to Laser Therapy
Benefits of Laser Therapy
Versatility of Laser Therapy
KnowledgeBase Articles
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for a Keyword:
- What is wavelength and why is it important?
- Which wavelengths have the most interactions on which materials in the body?
- Why 980nm wavelength is less than optimal?
- How does Laser work to heal the body?
- TOBI Comes When You Call
- Implementation Strategies
- 3 Common Mistakes Veterinarians Make When Administering Laser Therapy (AND How to Avoid Them)
- TOBI Comes When You Call
- How Much Does a Therapy Laser Cost?
- Laser On Wounds
- Stimulating Circulation
- Frontiers of Laser Therapy
- Systemic Effects of Laser Therapy
- Laser as Adjunct with Stem Cells and PRP
- Pulsing in Laser Therapy
Everything You Need, Nothing You Dont
NEED Class IV power to treat large treatment volumes in short time Aside from superficial wound treatments, laser treatment requires the delivery of dose at depth within the patient. The body greatly attenuates the amount of light delivered, and so the amount of light needed to be clinically therapeutic increases as the treatment volume increases (i.e. as the surface area of the treatment zone OR the depth of the injury increases). Delivering useful dose prescriptions to relevant anatomies in feasible treatment times requires Class IV power.
DON'T NEED 15 Watts of power, a dangerous tool to even a slightly distracted tech The pain threshold to the heat delivered by laser absorption is around 1-2 Watt/cm2 of power density. The typical treatment size for most Class IV therapy lasers is 10 cm2 (on the high side). This means that delivering 15 Watts of power, while it would serve to shorten treatment times, would fall dangerously close if not above the pain threshold. Laser companies advise you to move the handpiece more quickly as you scan to avoid this heat, but if the laser administrator becomes even the slightest bit distracted or pauses over a single area, they can inflict immediate pain in the patient. Also noteworthy is that even for laser’s with this high power capacity, there are virtually NO pre-set protocols that employ such a high power.
NEED Wavelengths that penetrate and target biological chromophores The therapeutic effects of light come from absorption on some key chromophores within tissues and constituent cells in the body. These materials, such as the mitochondria of cells and hemoglobin in the blood, have been shown to effectively absorb in the visible-to-near-infrared spectrum. Fortunately in this portion of the spectrum, there is also a window of translucency, where the barriers of penetration (like melanin and water) do not absorb very well at all, allowing for significantly deeper penetration of therapeutic light.
DON'T NEED A wavelength that targets only water, only to produce heat Since the body is made up of about 80% water, even wavelengths of light that absorb relatively weakly in water, still do in fact end up absorbed in water (they don’t continue in a beam through the body exiting the other side). So targeting water directly with a wavelength that coincides with a peak of water’s absorption (i.e. 960-980nm) leads to a quicker and more efficient conversion of light into heat. This inhibits penetration and leads to local thermal accumulation, which beyond simply heating the tissue, doesn’t have much benefit therapeutically. The key chromophores mentioned above (those that DO promote therapy) exponentially decrease in absorption efficiency above around 940nm.
NEED Frequencies that span the range of the tissues in the body The response of individual tissues in the body depends greatly on the delivery method of the therapy, in particular the pulse frequency of the light delivered. Bone and soft tissue are on opposite sides of this spectrum and so it is of utmost importance to use frequencies that span this therapeutic range, from 1 Hz all the way up to 15-25,000 Hz. In fact, in any given injury several tissues are often involved, and so each protocol should employ several frequencies to have highest probability of target each of the tissues present in the treatment volume.
DON'T NEED Ten-to-Twelve ultra-short phases per treatment When delivering each “phase” of treatment, there must be enough time to target the intended tissue type. If there are too many phases within a fixed treatment time, then the individual “phase” time is only a few seconds, and not nearly enough time to cover the entire treatment area. For example, eleven phases on a 2 minute treatment is 11 seconds per phase.
NEED A quick and easy way to get a tailored protocol There is a necessary balance between ease-of-use and the election of an appropriate protocol. The interface needs to be both useful and repeatable with no ambiguity. With precise programming, it is possible with three button-touches to differentiate a small post-surgical wound from the hip dysplasia of a large light-colored dog from the shoulder arthritis of a dark-haired cat.
DON'T NEED To touch the screen 11 times to treat a dog, then to have to start all over to repeat the treatment On most commercial lasers, there are only 3 virtual “knobs” to turn (i.e. power, frequency, and time) and often only two. Yet on some of these, there are over 10 selections to make. This false façade of complexity is meant to provide a sense of confidence in the precision of the therapy. Upon further inspection, however, you’d notice that only a couple of the protocol selections actually change any meaningful output parameters. Opting between arthritis and tendonitis of the same joint, for example, make no changes at all, nor should they. But then why the ambiguity and the forced selection?
NEED Consistency from treatment to treatment (TOBI) Treatment efficacy depends both on appropriate parameters and sound treatment technique. Consistency of parameters is easy with the 1-2-3 protocol selection process. Consistency of treatments comes with proper training and understanding of the principles of laser therapy. doctorVet’s treatment assistant TOBI teaches both with every treatment. Step-by-step guidance through every protocol in doctorVet’s arsenal including advice on how often to treat and how to modify treatments based on the patient response makes outcomes from laser therapy as predictable as possible.
DON'T NEED On-board database to store default protocols just with different names and timestamps No current laser has full integration with any practice management software (PMS), mostly because there are so many different PMS systems out there. If you want records of the history of your patients, whether laser treatments or anything else, you dont look to the device, you look to your PMS since it has all diagnostic and treatment information in one place. Also, since PMS serves as a valuable tool for identifying your candidate caseload for laser therapy, you would much rather have the information there up-to-date. No need for the dual data-entry.
NEED Consistency from tech to tech (TOBI) The last thing you want is a pet-owner requesting which technician they want to treat their animal. Your business is built on consistency and predictability regardless of which of your staff is attending to the patient. The key to this consistency is training. Not a one-time 3-hour training session at first implementation, but rather continual training based on each patient to be treated. TOBI provides expert, tailored advice based on each of the 30+ possible treatment classes in the 300+ protocols within the doctorVet platform.
DON'T NEED Complex modifications of default protocols Substantial protocol modification is only necessary in three instances: 1) when the pre-set protocols are not robust, 2) if your particular need is a rare injury, or 3) if you have years of experience that allow you to gain a significant advantage from your knowledge. doctorVet has been developed by expert clinicians, researchers, and engineers to fit the needs of the common majority of technicians and veterinarian clinics.
NEED Real-time advice on treatment technique Lasers are not magic wands. A lot of engineering and clinical expertise go into producing every laser, and just shining light onto your patient produces some wonderful results. But any experienced laser therapist will tell you that there is a skill and art in technique with intricacies that normally takes months-to-years to learn. TOBI teaches you every time you turn on the laser. Other laser manufacturers depend on an initial 1-2 day training, online support videos, and lots of trial-and- error for you to gradually become proficient. TOBI is an expert laser therapist who is by your side during every phase of every treatment constantly teaching you how to get the best results.
DON'T NEED iPad app with pretty graphics and generic summaries In an attempt to appear thoughtful and useful, some laser companies provide marketing material with fancy graphics and less-than-useful education materials. By witnessing a TOBI-guided laser therapy session on their pets, pet-owners will be educated in the science and methodology behind this useful modality, thereby increasing their awareness, compliance, and your revenue.
NEED Long term warranty that puts you at ease with your investment SOUND has long found that warrantied customers are the happiest customers. Unlike laser companies who have no reason to further engage you until your laser is due for an upgrade, SOUND has a vested interest in keeping you happy after the sale. We are the partner you keep, whether it be for digital radiography, ultrasound equipment, ultrasound education, or other Emerging technologies.
DON'T NEED Extra brochures and an iPad thrown it at point-of-sale In order to close deals, other laser companies often throw in marketing giveaways that have perceived, but empty value. SOUND focuses on the more important issues at point of sale: alternate treatment heads and iron-clad, long-term warranties that ensure optimal equipment performance for years after your initial investment.
Fundamental Actions of Laser Therapy
Laser absorption in water
Laser absorption in hemoglobin
Metabolic Stimulation
Laser absorption in mitochondria
The Big Picture
Evidence of Efficacy
Laser Literature
Search Publications for a Keyword:
Brain Parkinsons disease MPTPReinhart2016Neurosci ResThe behavioural and neuroprotective outcomes when 670 nm and 810 nm near infrared light are applied together in MPTP-treated miceMouse Note: In this paper, they had 6 different active treatment groups, and all of them fared better than the MPTP group!
Lymphedema Mayrovitz & Davey2011LymphologyChanges in tissue water and indentation resistance of lymphedematous limbs accompanying low level laser therapy (LLLT) of fibrotic skin.Human?
Skin Skin explants LLLT or LLLT+PDTde Jesus2016J BiophotonicsAn ex vivo study of photobiostimulation in the treatment of skin pathologies.Ex vivo.The results indicate that even at the early phase of the treatment (7 days), the LLLT at low doses 70 mJ ∙ cm–2 and 140 mJ ∙ cm–2 promotes the deposition of new collagen, slightly higher for 70 mJ ∙ cm–2, and the continuous irradiation with higher doses (700 mJ ∙ cm–2) increases the production of type I collagen
Respiratory system Lung inflammation Intratracheal LPS -> Lung inflammationCury2016J BiophotonicsLow level laser therapy reduces acute lung inflammation without impairing lung function.MouseSimilarly to other authors, we detected a significant increase in the expression of several pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), that was inhibited by laser treatment There was a marked increase in the expression of MCP-1 in the animals exposed to LPS, which was significantly reduced by laser irradiation. We suggest that this was one of the mechanisms by which LLLT reduced the number of inflammatory cells in the lung The LLLT application induced a significant decrease in both inflammatory cells influx and inflammatory mediators secretion. These effects did not affect lung mechanical properties, since no change was observed in tissue resistance or elastance. In conclusion LLLT is able to reduce inflammatory reaction in lungs exposed to LPS without affecting the pulmonary function and recovery.
Protozoa Paramecium Amaroli2015Photochem PhotobiolEffect of 808 nm Diode Laser on Swimming Behavior, Food Vacuole Formation and Endogenous ATP Production of Paramecium primaurelia (Protozoa).Protozoa(1) the 808 nm laser stimulates the P. primaurelia without a thermal effect, (2) the laser effect is demonstrated by an increase in swimming speed and in food vacuole formation, (3) the laser treatment affects endogenous adenosine triphosphate (ATP) production in a positive way, (4) the effects of irradiation dose suggest an optimum exposure time of 50 s (64 J cm(-2) of fluence) to stimulate the Paramecium cells; irradiation of 25 s shows no effect or only mild effects and irradiation up to 100 s does not increase the effect observed with 50 s of treatment, (5) the increment of endogenous ATP concentration highlights the positive photobiomodulating effect of the 808 nm laser and the optimal irradiation conditions by the flat-top handpiece.
Respiratory system Airway smooth muscle relaxation Aimbire2006Lasers Surg MedLow level laser therapy partially restores trachea muscle relaxation response in rats with tumor necrosis factor alpha-mediated smooth airway muscle dysfunction.In vitro[LLLT] partially restored TSM relaxation response to isoproterenol. Tension reduction was 47.0 % (+/-2.85) in the laser-irradiated group compared to 22.0% (+/-2.21) in the control group (P < 0.01). Accumulation of cAMP was almost normalized after LLLT at 22.3 pmol/mg (+/-2.1) compared to 17.6 pmol/mg (+/-2.1) in the non-irradiated control group (P < 0.01).
Oral Oral mucositis Sacono2008Lasers Surg MedLight-emitting diode therapy in chemotherapy-induced mucositis.Hamster[LLLT] was effective in reducing the severity of chemotherapy-induced mucositis in hamsters and contributed to the healing of the ulcerative oral lesions, though without preventing their occurrence completely Some possible harm was also noted, which might be related to high light intensity: However,18% of the specimens in this group presented musculardegeneration visible only by histological examination, withno clinical evidences.
Oral Oral mucositis Antunes2007BloodLow-power laser in the prevention of induced oral mucositis in bone marrow transplantation patients: a randomized trial.Human RCT5.3% of the laser group presented with ulcers of 9.1 cm2 to 18 cm2, whereas 73.6% of the control group presented with ulcers from 9.1 cm2 to 18 cm2 (P = .003). Our results indicate that the use of upfront LPLT in patients who have undergone HSCT is a powerful instrument in reducing the incidence of OM and is now standard in our center.
Eyes Light-induced damageChu-Tan2016Int J PhotoenergyEfficacy of 670 nm Light Therapy to Protect against Photoreceptor Cell Death Is Dependent on the Severity of DamageRat670 nm light exhibited a biphasic response in its amelioration of cell death in light-induced degeneration in vivo. Lower light damage intensities required lower doses of 670 nm light to reduce TUNEL cell death. At higher damage intensities, the highest dose of 670 nm light showed protection. In vitro, the Seahorse XFe96 Extracellular Flux Analyzer revealed that 670 nm light directly influences mitochondrial metabolism by increasing the spare respiratory capacity of mitochondria in 661 W photoreceptor-like cells in light damaged conditions. Our findings further support the use of 670 nm light as an effective treatment against retinal degeneration as well as shedding light on the mechanism of protection through the increase of the mitochondrial spare respiratory capacity.
Eyes Oxygen-induced damage & Lung damageNatoli2013PLoS One670nm photobiomodulation as a novel protection against retinopathy of prematurity: evidence from oxygen induced retinopathy models.Mouse & Rat670 nm light reduced neovascularisation, vaso-obliteration and abnormal peripheral branching patterns of retinal vessels in OIR. The neural retina was also protected against OIR by 670 nm light exposure. OIR-exposed animals had severe lung pathology, including haemorrhage and oedema, that was significantly reduced in 670 nm+OIR light-exposed animals.
Nerves Neuronal growth Biphasic dose responseRochkind2009Lasers Surg MedIncrease of neuronal sprouting and migration using 780 nm laser phototherapy as procedure for cell therapy.In vitro780 nm laser phototherapy of embryonic rat brain cultures embedded in hyaluronic acid-laminin gel and attached to positively charged cylindrical MCs, stimulated migration and fiber sprouting of neuronal cells aggregates, developed large size neurons with dense branched interconnected network of neuronal fibers and, therefore, can be considered as potential procedure for cell therapy of neuronal injury or disease.
Wound healing Wounds Biphasic dose response Laser vs non-coherentDemidova-Rice2007Lasers Surg MedLow-level light stimulates excisional wound healing in mice.Mouse820 nm is the most effective wavelength laser and non-coherent lamp are equivalent LLLT stimulates wound contraction in susceptible mouse strains but the mechanism remains uncertain.
Oncology Human research Mikhailov2000Proc. SPIE 4166Results of treatment of patients with second- to third-stage breast cancer by combination of low-level laser therapy (LLLT) and surgery: ten-year experienceHuman86.9% (76.19% in control group) of patients with stage II breast cancer survived 10 years after LLLT treatment. For patients with stage III breast cancer treated by LLLT the rate was 83.3% (68.4% in control group).
Wound healing Wounds Leclère2010Wound Repair RegenA prospective randomized study of 980 nm diode laser-assisted venous ulcer healing on 34 patients.Human Observational980 nm diode laser-assisted venous ulcer healing was easy to perform and very well tolerated. However, there were no statistically significant differences in reduction of ulcer size between the two groups, suggesting that this particular laser regimen does not promote wound healing. Note: This paper isnt actually LLLT, since a very high dose laser was used and it led to significant heating of the irradiated tissue.
Circulation Microcirculation MIRE treatment with Anodyne LED pad deviceMak & Cheing2012Photomed Laser SurgImmediate effects of monochromatic infrared energy on microcirculation in healthy subjects.Human RCTA 30-min MIRE produced a significantly greater increase in the capillar blood velocity (CBV) and flux of the feet in the active MIRE group than in the placebo and control groups.
Pain Nociception Dose response (?)Laakso & Cabot2005Photomed Laser SurgNociceptive scores and endorphin-containing cells reduced by low-level laser therapy (LLLT) in inflamed paws of Wistar rat.RatA dose of 1 J/cm(2) had no statistically significant effect on antinociceptive responses. A dose of 2.5 J/cm(2) demonstrated a statistically significant effect on paw pressure threshold ( p < 0.029) compared to controls. There was no difference in paw thermal threshold responses and paw volumes at either dose.
Oral Denture stomatitis Maver-Biscanin2004Lasers Surg MedFungicidal effect of diode laser irradiation in patients with denture stomatitis.Human RCTA fungicidal effect was achieved in the laser treated and antimicotic treated groups, whereas most subjects in the placebo group were found to have unchanged conditions
Oral Periodontium Pejcic2010Photomed Laser SurgThe effects of low level laser irradiation on gingival inflammation.HumanA general conclusion can be drawn that low level laser irradiation (semiconductor, 670 nm) can be used as a successful physical adjuvant method of treatment, which, together with traditional periodontal therapy, leads to better and longer-lasting therapeutic results.
Mechanisms Original research Isolated liver mitochondriaPastore1994Biochem Mol Biol IntIncrease in <--H+/e- ratio of the cytochrome c oxidase reaction in mitochondria irradiated with helium-neon laser.In vitroA low, but statistically significant increase in the oxygen uptake was found, as polarographically measured, in the presence of rotenone and antimycin A, with ascorbate and TMPD used as substrate pair. Measurements were also made both of the electron transfer and of proton pumping activity: as a result of a major stimulation in the proton pumping activity, about 55% increase of <--H+/e- ratio was found in irradiated mitochondria.
LED technology Lim2015Mol Cryst Liq CrystRed/Infrared LED Unit with Moderate Light Intensity and Low Heat Generation for Personal Phototherapy ApplicationsA new phototherapy unit for personal and home application is developed based on red and infrared LEDs.
Edema Paw Inflammatory paw edema by carrageenanAlbertini2008Photomed Laser SurgCytokine mRNA expression is decreased in the subplantar muscle of rat paw subjected to carrageenan-induced inflammation after low-level laser therapy.RatA pronounced swelling of the rat paw was observed 4 h after treatment with carrageenan in comparison to the control group. Edema formation was decreased by LLLT with wavelengths of both 660 and 684 nm (Fig. 1). Both the 660 nm and 684 nm laser groups had 30%-40% lower mRNA expression for cytokines TNF-alpha, IL-1beta, and IL-6 in the paw muscle tissue than the carrageenan-only control group. Cytokine measurements were made 3 h after laser irradiation of the paw muscle, and all cytokine differences between the carrageenan-only control group and the LLLT groups were statistically significant (p < 0.001). Comment: The results are quite notable and interesting.
Flatworms Dugesia tigrina de Souza2005J Photochem Photobiol BLow power laser radiation at 685 nm stimulates stem-cell proliferation rate in Dugesia tigrina during regeneration.Dugesia tigrinaA remarkable increase in stem cells counts for the fourth day of regeneration was observed when the regenerating worms was stimulated by the laser radiation. Our findings encourage further research works on the influence of optical radiation onto stem cells and tissue regeneration.
Fertility, genitals, etc. Nipple trauma LED phototherapyChaves2012Photomed Laser SurgLED phototherapy improves healing of nipple trauma: a pilot study.Human ControlledA significant difference between the experimental and control groups was observed for the healing of nipple lesions (p<0.001). The pain intensity was significantly reduced only in the experimental group (p<0.001). Preliminary results demonstrated the prototype apparatus for LED phototherapy to be an effective tool in accelerating the healing of nipple trauma. Comment: The baseline pain was higher in LED phototherapy group, so the reductions are difficult to compare.
Oral Oral mucositis Patients undergoing HSCTBezinelli2016Eur J Cancer Care (Engl)Quality of life related to oral mucositis of patients undergoing haematopoietic stem cell transplantation and receiving specialised oral care with low-level laser therapy: a prospective observational study.Human ObservationalA significant number of patients (46.38%) had grade 1 mucositis (indicating no ulcers in the oral cavity). The study showed that QoL improves over time in these patients undergoing LLLT therapy for prevention of mucositis.
Brain Depression Disner2016Brain StimulTranscranial Laser Stimulation as Neuroenhancement for Attention Bias Modification in Adults with Elevated Depression Symptoms.Human RCT/SB (?)A significant three-way interaction between LLLT condition, ABM response, and time indicated that right LLLT led to greater symptom improvement among participants whose attention was responsive to ABM (i.e., attention was directed away from negative stimuli). Minimal change in depression was observed in the left and sham LLLT. The results suggest that larger clinical trials examining the efficacy of using photoneuromodulation to augment cognitive training are warranted.
Respiratory system COPD Muscle functionMiranda2014Lasers Med SciAcute effects of light emitting diodes therapy (LEDT) in muscle function during isometric exercise in patients with chronic obstructive pulmonary disease: preliminary results of a randomized controlled trial.Human RCTA single application of LEDT minimizes muscle fatigue and increases isometric endurance time.
Cells Protection Biphasic dose responseHawkins & Abrahamse2006Photomed Laser SurgEffect of multiple exposures of low-level laser therapy on the cellular responses of wounded human skin fibroblasts.In vitroA single dose of 5.0 J/cm(2), and two or three doses of 2.5 J/cm(2) had a stimulatory or positive effect on wounded fibroblasts with an increase in cell migration and cell proliferation while maintaining cell viability, but without causing additional stress or damage to the cells. Multiple exposures at higher doses (16 J/cm(2)) caused additional stress, which reduces cell migration, cell viability, and ATP activity, and inhibits cell proliferation.
Oral Tooth extraction Pedreira2016Minerva StomatolThermographic and clinical evaluation of 808-nm laser photobiomodulation effects after third molar extraction.HumanA slight improvement was observed for swelling, pain and trismus in patients who received laser irradiation, although the differences were not statistically significant (P>0.05). Laser therapy had a significant influence on the local circulation in the area near the temporomandibular joint, as determined by infrared thermography (P<0.05).
Oral Orthodontics Tooth movementAlSayed Hasan2016 epubAngle OrthodLow-level laser therapy effectiveness in accelerating orthodontic tooth movement: A randomized controlled clinical trial.Human RCTA statistically significant difference was found between the two groups in the overall treatment time (P < .001) and the leveling and alignment improvement percentage at T1 (P = .004) and T2; (P = .001).
Oral Burning mouth syndrome Sugaya2016Braz Oral ResLow Intensity laser therapy in patients with burning mouth syndrome: a randomized, placebo-controlled study.Human RCTAccording to the protocol used in this study, low intensity laser therapy is as beneficial to patients with BMS as placebo treatment, indicating a great emotional component of involvement in BMS symptomatology. Nevertheless, there were positive results in some statistical analyses, thus encouraging further research in BMS laser therapy with other irradiation parameters.
Nerves PNS Fibular nerveSousa2013Acta Ortop BrasLack of effectiveness of laser therapy applied to the nerve course and the correspondent medullary roots.RatAccording to the statistical analysis there was no significant difference among groups and the authors conclude that low intensity laser irradiation has little or no influence on nerve regeneration and functional recovery.
Nerves PNS Rochkind1987Lasers Surg MedResponse of peripheral nerve to He-Ne laser: experimental studies.RatAction potential (AP) in the healthy nerve increased by 33% following a single transcutaneous irradiation. Similar irradiation in crushed nerves caused AP to increase significantly over the AP of nonirradiated crushed nerve. Morphological observations revealed that a laser-irradiated injured nerve had diminished scar tissue as compared to an injured but not an irradiated nerve.
Muscle Exercise LED phototherapy LED cluster (69)Leal Junior2009Lasers Surg MedEffect of cluster multi-diode light emitting diode therapy (LEDT) on exercise-induced skeletal muscle fatigue and skeletal muscle recovery in humans.Human RCT/DB CrossoverActive LEDT increased the number of biceps humeri contractions by 12.9% (38.60 [SD +/-9.03] vs. 34.20 [SD +/-8.68], P = 0.021) and extended the elapsed time to perform contractions by 11.6% (P = 0.036) versus placebo. In addition, post-exercise levels of biochemical markers decreased significantly with active LEDT: Blood Lactate (P = 0.042), Creatine Kinase (P = 0.035), and C-Reative Protein levels (P = 0.030), when compared to placebo LEDT.
Muscle Exercise LLLT cluster (5)Leal Junior2010J Orthop Sports Phys TherEffects of low-level laser therapy (LLLT) in the development of exercise-induced skeletal muscle fatigue and changes in biochemical markers related to postexercise recovery.HumanActive LLLT increased the number of repetitions by 14.5% (mean +/- SD, 39.6 +/- 4.3 versus 34.6 +/- 5.6; P = .037) and the elapsed time before exhaustion by 8.0% (P = .034), when compared to the placebo treatment. The biochemical markers also indicated that recovery may be positively affected by LLLT, as indicated by postexercise blood lactate levels (P<.01), creatine kinase activity (P = .017), and C-reactive protein levels (P = .047), showing a faster recovery with LLLT application prior to the exercise.
Brain Depression Tanaka2011Brain StimulInfrared radiation has potential antidepressant and anxiolytic effects in animal model of depression and anxiety.RatAcutely exposed rats were treated with an infrared radiation machine for one session, whereas chronically exposed animals were treated with an infrared radiation for 10 sessions. The infrared emitter had highest emissivity values within 0.6-1.6 μm and a calculated maximal irradiation intensity of 1800-2200 mW. A polyethylene restraint apparatus (a device that modeled the neck and the body of the animal as cylinders and the head as an ellipsoid) was used to immobilize the head and body of the rat during the treatment. Chronic infrared radiation exposure decreased indicators of depression- and anxiety-like behavior. No significant effect on general locomotor activity was observed. The number of BrdU-positive cells in CA1 of the hippocampus was significantly increased in both acutely and chronically exposed infrared radiation groups compared with the control group. These results indicate that chronic infrared radiation might produce antidepressant- and anxiolytic-like effects.
Hair Androgenetic alopeciaKim2013Dermatol SurgLow-level light therapy for androgenetic alopecia: a 24-week, randomized, double-blind, sham device-controlled multicenter trial.Human RCT/DBAfter 24 weeks of treatment, the LLLT group showed significantly greater hair density than the sham device group. Mean hair diameter improved statistically significantly more in the LLLT group than in the sham device group. Investigator global assessment showed a significant difference between the two groups, but that of the subject did not.
Pain Nociception Tsuchiya1993Neurosci LettDiode laser irradiation selectively diminishes slow component of axonal volleys to dorsal roots from the saphenous nerve in the rat.RatAfter 3 min irradiation, slowest conduction velocity group (< 1.3 m/s) were totally diminished and 1.3-12 m/s group were reduced to 12-67%. In contrast, faster component (> 12 m/s) was unaffected by laser irradiation. These findings suggest that laser irradiation may selectively target fibers conducting at slow velocities which include afferent axons from nociceptors.
Gastroenterology Atrophic gastritis Biphasic dose responseShao2005World J GastroenterolEffects of He-Ne laser irradiation on chronic atrophic gastritis in rats.RatAfter 3.36 J/cm(2) dose of He-Ne laser treatment for 20 d, the secretion of gastric acid was increased (P<0.05), the thickness of gastric mucosa was significantly thicker than that in model control group (P<0.01), the gastric mucosal inflammation cells were decreased (P<0.05). Morphology, structure and volume of the parietal cells all recuperated or were closed to normal. Comment: In higher dose groups, no benefit was noted.
Joints Osteoarthritis S2016 epubLasers Med SciRadiological and biochemical effects (CTX-II, MMP-3, 8, and 13) of low-level laser therapy (LLLT) in chronic osteoarthritis in Al-Kharj, Saudi Arabia.After 4- and 8-week treatment, active laser group shows more significant difference (p < 0.001) in all the parameters than the placebo laser group (p > 0.05). Our results show that low-level laser therapy was more efficient in reducing pain and improving cartilage thickness through biochemical changes. Star: In this study, the improvement in LLLT versus placebo is huge. Maybe they found some good parameters for the treatment of knee osteoarthritis?
Nerves PNS Harmful effects from LLLTChen2005MicrosurgeryEffect of low-power pulsed laser on peripheral nerve regeneration in rats.RatAfter 8 weeks of recovery, pulsed laser-irradiated groups at frequencies of 5 kHz and 20 kHz both had significantly lower success percentages of regeneration (50% and 44%, respectively) compared to sham-irradiated controls (100%). In addition, qualitative and quantitative histology of the regenerated nerves revealed a less mature ultrastructural organization with a smaller cross-sectional area and a lower number of myelinated axons in both pulsed laser-irradiated groups than in controls. These results suggest that pulsed laser irradiation could elicit suppressing effects on regenerating nerves. Jan Tunér published a comment on this paper, mentioning some interesting things: [see Additional info]
Hearing Tinnitus Tauber2003Lasers Med SciTransmeatal cochlear laser (TCL) treatment of cochlear dysfunction: a feasibility study for chronic tinnitus.Human Pilot studyAfter a follow-up period of six months tinnitus loudness was attenuated in 13 of 35 irradiated patients, while two of 35 patients reported their tinnitus as totally absent. Hearing threshold levels and middle ear function remained unchanged.
Diabetes mellitus Ulcers and wounds Diabetic microangiopathySchindl1998Diabetes CareLow-intensity laser irradiation improves skin circulation in patients with diabetic microangiopathy.Human RCT/DBAfter a single transcutaneous low-intensity laser irradiation, a statistically significant rise in skin temperature was noted (P < 0.001 by ANOVA for repeated measurements), whereas in the sham-irradiated control group, a slight but significant drop in temperature (P < 0.001) was found.
Muscle Exercise Leal Junior2009Lasers Med SciEffect of 830 nm low-level laser therapy in exercise-induced skeletal muscle fatigue in humans.Human RCT/DB CrossoverAfter active LLLT the mean number of repetitions was significantly higher than after placebo irradiation [mean difference 4.5, standard deviation (SD) +/- 6.0, P = 0.042], the blood lactate levels increased after exercises, but there was no significant difference between the treatments. We concluded that 830 nm LLLT can delay the onset of skeletal muscle fatigue in high-intensity exercises, in spite of increased blood lactate levels.
Oral Periodontium Obradović2011Vojnosanit Pregl[Low power laser efficacy in the therapy of inflamed gingive in diabetics with parodontopathy]. [Article in Serbian]HumanAfter all investigated periods, gingival index and nuclei areal were significantly decreased comparing to values before the therapy, at both jaw sides (p < 0.001). After the 1st, 3rd and 5th therapy, the t-test showed a significantly decreased gingival index at the lased side of jaw comparing to non-lased side. Low level laser therapy is efficient in gingival inflammation elimination and can be proposed as an adjuvant tool in basic periodontal therapy of diabetic patients.
Skin Vitiligo Wu2008Kaohsiung J Med SciLow-energy helium-neon laser therapy induces repigmentation and improves the abnormalities of cutaneous microcirculation in segmental-type vitiligo lesions.HumanAfter an average of 17 treatment sessions, initial repigmentation was noticed in the majority of patients. Marked repigmentation (> 50%) was observed in 60% of patients with successive treatments. Cutaneous blood flow was significantly higher at SV lesions compared with contralateral skin, but this was normalized after He-Ne laser treatment. In addition, the abnormal decrease in cutaneous blood flow in response to clonidine was improved by He-Ne laser therapy. Our study showed that He-Ne laser therapy is an effective treatment for SV by normalizing dysfunctions of cutaneous blood flow and adrenoceptor responses in SV patients. Thus, the beneficial effects of He-Ne laser therapy may be mediated in part by a reparative effect on sympathetic nerve dysfunction.
Muscle Spasticity dos Reis2015Lasers Med SciImmediate effects of low-intensity laser (808 nm) on fatigue and strength of spastic muscle.Human DBBAfter application of LILT, we found increased torque as well as decreased in lactate level in patients with spasticity.
Wound healing Wounds Simunovic2000J Clin Laser Med SurgWound healing of animal and human body sport and traffic accident injuries using low-level laser therapy treatment: a randomized clinical study of seventy-four patients with control group.HumanAfter comparing the healing process between two groups of patients, we obtained the following results: wound healing was significantly accelerated (25%-35%) in the group of patients treated with LLLT. Pain relief and functional recovery of patients treated with LLLT were significantly improved comparing to untreated patients.
Wound healing Surgical wounds Diabetic patient Delayed CABG sternotomy wound healing LED phototherapy LED cluster (34+35)Dixit2013Indian J Palliat CarePhotobiomodulation of surgical wound dehiscence in a diabetic individual by low-level laser therapy following median sternotomy.Human Case reportAfter irradiation, proliferation of healthy granulation tissue was observed with decrease in scores of PUSH for sternal dehiscence and VAS for bilateral shoulders and sternal dehiscence. We found that LLLT irradiation could be a novel method of treatment for chronic sternal dehiscence following coronary artery bypass grafting, as it augments wound healing with an early closure of the wound deficit.
Heart MI MIZhang2010J Cell Mol MedLow level laser irradiation precondition to create friendly milieu of infarcted myocardium and enhance early survival of transplanted bone marrow cells.RatAfter LLLI precondition, increased VEGF and GRP78 expression, as well as the enhanced SOD activity and inhibited MDA production, was observed. Compared with BMSC transplantation and culture media injection group, although there was no difference in the improved heart function and myogenic differentiation, LLLI precondition significantly enhanced early cell survival rate by 2-fold, decreased the apoptotic percentage of implanted BMSCs in infarcted myocardium and thus increased the number of newly formed capillaries. Taken together, LLLI precondition could be a novel non-invasive approach for intraoperative cell transplantation to enhance cell early survival and therapeutic potential.
Oral Oral mucositis LED phototherapy LLLT vs LED WavelengthsCampos2016J BiophotonicsComparative study among three different phototherapy protocols to treat chemotherapy-induced oral mucositis in hamsters.HamsterAfter statistical analysis, the authors results showed LED and LLLT therapies were efficient treatments for OM, decreasing TNF-α concentration on day 7 (p < 0.05) and completely healing the mucosa on day 10. HPL showed no interference in final healing of OM. According to the methodology used and the results obtained in the present study, LLLT and LED therapies were the best choices to decrease the severity of OM, accelerating tissue repair and decreasing the inflammatory process.
Muscle Spasticity Stroke patientsdas Neves2016Lasers Med SciEffects of low-level laser therapy (LLLT 808 nm) on lower limb spastic muscle activity in chronic stroke patients.Human DBAfter the real LLLT intervention, we observed significant reduction in the visual analogue scale for pain intensity (p = 0.0038), increased time to onset of muscle fatigue (p = 0.0063), and increased torque peak (p = 0.0076), but no significant change in the root mean square (RMS) value (electric signal in the motor unit during contraction, as obtained with surface electromyography). Our results suggest that the application of LLLT may contribute to increased recruitment of muscle fibers and, hence, to increase the onset time of the spastic muscle fatigue, reducing pain intensity in stroke patients with spasticity, as has been observed in healthy subjects and athletes.
Oral TMJ Peimani & Sardary2014J Dent (Tehran)Effect of low-level laser on healing of temporomandibular joint osteoarthritis in rats.RatAfter three days of treatment the grade of cartilage defects, number of inflammatory cells, angiogenesis, number of cell layers and arthritis in rats in the case group were not significantly different compared with controls (P>0.05). After seven days, the grade of cartilage defects, number of inflammatory cells, number of cell layers, and arthritis in the case group improved compared to controls (P<0.05); angiogenesis in both groups was similar.
Bone Fractures Chang2014Photomed Laser SurgTherapeutic outcomes of low-level laser therapy for closed bone fracture in the human wrist and hand.Human RCT/SBAfter treatment and at the follow-up, the laser group exhibited significant changes in all of the parameters compared with the baseline (p<0.05). The results of comparing the two groups after treatment and at the follow-up indicated significant between-group differences among all of the parameters (p<0.05). Comment: The results are quite remarkable.
Eyes Age-related macular degenerationKokkinopoulos2013Neurobiol AgingAge-related retinal inflammation is reduced by 670 nm light via increased mitochondrial membrane potential.MouseAged mice were exposed to only five 90-second exposures over 35 hours. This significantly increased mitochondrial membrane polarization and significantly reduced macrophage numbers and tumor necrosis factor (TNF)-alpha levels, a key proinflammatory cytokine. Three additional inflammatory markers were assessed; complement component 3d (C3d), a marker of chronic inflammation and calcitonin, and a systemic inflammatory biomarker were significantly reduced. Complement component 3b (C3b), a marker of acute inflammation, was not significantly altered. These results provide a simple route to combating inflammation in an aging population with declining visual function and may be applicable to clinical conditions where retinal inflammation is a key feature.
Cells Energy metabolism Osteoblasts FibroblastsQuirk2016J Clin Orthop TraumaEffect of near-infrared light on in vitro cellular ATP production of osteoblasts and fibroblasts and on fracture healing with intramedullary fixation.In vitroAll groups gave significant increase in ATP within 5-10 min, with decay to baseline by 45 min. 660 nm NIR was significantly more effective than 830 nm with fibroblasts or either wavelength with osteoblasts. Animal study - A significant increase in the fracture healing grade in the 660 nm group at day 14, but with no differences at day 21.
Pain Neuropathic Parris1994Anesth ProgInfrared laser diode irradiation has no behavioral or biochemical effect on pain in the sciatic nerve ligation-induced mononeuropathy in rat.RatAll modalities of IR diode laser treatment did not produce any significant difference in the brain and spinal cord level of DYN on postoperative day 9 in all treatment groups. It is concluded that repeated IR diode laser treatment did not reduce hyperalgesia induced by sciatic nerve ligation in rats.
Pain Shoulder Subacromial impingement syndromeKibar2016Pain MedLaser Acupuncture Treatment Improves Pain and Functional Status in Patients with Subacromial Impingement Syndrome: A Randomized, Double-Blind, Sham-Controlled Study.Human RCT/DBAll parameters of pain and functional status in the treatment group were significantly better than those in the control group at week 3.
Oral Oral mucositis Jaguar2007Oral DisLow-energy laser therapy for prevention of oral mucositis in hematopoietic stem cell transplantation.Human ObservationalAll patients developed some grade of mucositis. However, the L- group presented initial mucositis by 4.36 days, whereas the L+ group presented it in 6.12 days (P = 0.01). The maximum mucositis occurred between day +2 and day +6 with healing by day +25 in the L- group and between day +2 and day +7 with healing by day +14 for the L+ group (P = 0.84). Laser therapy also reduced the time of oral pain from 5.64 to 2.45 days (P = 0.04), and decreased the consumption of morphine (P = 0.07). Comment: The parameters were poorly reported.
Pain Back pain LLLT vs lidocaine PBM of dorsal root ganglion (DRG) Photon Lase III® DCM, BrazilHolanda2016Lasers Surg MedPhotobiomodulation of the dorsal root ganglion for the treatment of low back pain: A pilot study.Human Comparison trialAll patients in the local anesthetic and laser treatment groups reported a pain reduction of at least 50% immediately post-procedure and 10 out of 11 patients in the radiofrequency group reported a pain reduction of at least 50%. At 1 month post-treatment, the laser treatment group had the greatest number of patients who reported more than 50% pain relief based on PRS (7 out of 10 patients) while only 2 out of 7 patients and 3 out of 11 patients in the lidocaine and radiofrequency treatment groups respectively reported more than a 50% pain relief. Laser irradiation caused an immediate decrease in low back pain post-procedure similar to pain reduction caused by lidocaine injection.
Oral Burning mouth syndrome dos Santos Lde2011Photomed Laser SurgEffect of low-level laser therapy in the treatment of burning mouth syndrome: a case series.Human Case seriesAll patients reported improvement in all sessions, with reduction in VAS scores by up to 58% in the tenth session.
Oral Oral mucositis Dose comparison No control groupSimões2009Lasers Surg MedLaser phototherapy as topical prophylaxis against head and neck cancer radiotherapy-induced oral mucositis: comparison between low and high/low power lasers.Human ObservationalAll protocols of LPT led to the maintenance of oral mucositis scores in the same levels until the last RT session. Moreover, LPT three times a week also maintained the pain levels. However, the patients submitted to the once a week LPT had significant pain increase; and the association of low/high LPT led to increased healing time.
Brain Alzheimers Disease Transgenic mice (amyloid-β protein precursor)De Taboada2011J Alzheimers DisTranscranial laser therapy attenuates amyloid-β peptide neuropathology in amyloid-β protein precursor transgenic mice.MouseAll TLT doses produced an increase in sAβPPα and a decrease in CTFβ levels consistent with inhibition of the β-secretase activity. In addition, TLT showed an increase in ATP levels, mitochondrial function, and c-fos suggesting an overall improvement in neurological function. These studies suggest that TLT is a potential candidate for treatment of AD.
Oral Mucoleles Amaral2012Lasers Med SciLow level laser effect after micro-marsupialization technique in treating ranulas and mucoceles: a case series report.Human Case seriesAll treated oral ranulas and selected mucoceles presented clinical healing. No evidence of recurrence could be identified during a mean of 11.0-month follow-up period. The use of InGaAsP diode lasers, within the parameters tested, appears to present a good alternative treatment to reduce pain and heal oral ranulas and selected mucoceles associated with micro-marsupialization.
Oral Burning mouth syndrome dos Santos Lde2015Photochem PhotobiolPhototherapy on the Treatment of Burning Mouth Syndrome: A Prospective Analysis of 20 Cases.Human Case seriesAll volunteers reported reduced burning intensity in all sessions when compared to the previous one and reduction in VAS scores by up to 49% in the last clinical session when compared to the first session.
Tendons Achilles tendon TenotomyCarrinho2006Photomed Laser SurgComparative study using 685-nm and 830-nm lasers in the tissue repair of tenotomized tendons in the mouse.MouseAll wavelengths and fluences used in this study were efficient at accelerating the healing process of Achilles tendon post-tenotomy, particularly after the 685-nm laser irradiation, at 3 J/cm(2). It suggests the existence of wavelength tissue specificity and dose dependency.
Respiratory system Allergic rhinitis Allergic rhinitis Nasal polyposis LED phototherapy BioNase LED lightNeuman&Finkelstein1997Ann Allergy Asthma ImmunolNarrow-band red light phototherapy in perennial allergic rhinitis and nasal polyposis.Human RCT/DB (?)Allergic rhinitis, if uncomplicated by polyps or chronic sinusitis, can be effectively treated by narrow-band red light illumination of the nasal mucosa at 660 nm, with marked alleviation of clinical symptoms. Comment: If I remember correctly, the sham group results in abstract contradict a little bit with the results presented in full text (improvement in 3% vs 21%). Comment: The sham-controlling is suboptimal, since its bright red light vs no light.
Brain Depression Meesters1999Biol PsychiatryProphylactic treatment of seasonal affective disorder (SAD) by using light visors: bright white or infrared light?HumanAlmost every light fixture produces light with an infrared component. So, our data indicate that, if light is crucial to the response, it must be that component which is crucial. However, infrared light is beyond the visible range of the spectrum. The 720 nm filter in our light visor still transmitted some visible light. However, its visibility was virtually negligible (0.18 lux). The conclusion of this study might therefore be that the perception of light does not play a role in the therapeutic mechanism. Infrared might be effective through pathways other than those involved in perception. Infrared light is just as effective as bright white light. Both are more effective than the control condition. Comment: In this study, they used a 720nm filter for the bright light to show that the effects of bright light might be mediated by the infrared, not visible light wavelengths.
Carpal tunnel Carpal tunnel syndrome Dakowicz2011Adv Med SciComparison of the long-term effectiveness of physiotherapy programs with low-level laser therapy and pulsed magnetic field in patients with carpal tunnel syndrome.Human RCT Comparison trialAlthough after LLL as well as PMF therapy clinical improvement was observed, the most significant differences were registered after the second series and persisted for up to 6 months in both groups.
Heart MI MIYang2011Photomed Laser SurgLow-level laser irradiation alters cardiac cytokine expression following acute myocardial infarction: a potential mechanism for laser therapy.RatAlthough LLLI did not improve the damaged heart function, it did reduce the infarct area expansion.
Cells Protection Primary cortical neurons Hydrogen peroxide / cobalt chloride / rotenoneHuang2013J BiophotonicsLow-level laser therapy (LLLT) reduces oxidative stress in primary cortical neurons in vitro.In vitroAlthough LLLT increases ROS in normal neurons, it reduces ROS in oxidatively-stressed neurons. In both cases MMP is increased. These data may explain how LLLT can reduce clinical oxidative stress in various lesions while increasing ROS in cells in vitro.
Thyroid Hormones Weber2014Photomed Laser SurgEffect of three different protocols of low-level laser therapy on thyroid hormone production after dental implant placement in an experimental rabbit model.RabbitAlthough not reaching abnormal values, LLLT applied to the mandible influenced thyroid function in this model.
Nerves In vitro LED phototherapyBurland2015J BiophotonicsNeurite growth acceleration of adult Dorsal Root Ganglion neurons illuminated by low-level Light Emitting Diode light at 645 nm.In vitroAlthough the axotomized neurons were naturally already in a rapid regeneration process, an enhancement was found to occur while irradiating with the LED light, which may be promising for therapy applications.
Oral Orthodontics Tooth movementYassaei2016Lasers Med SciEffects of diode laser (980 nm) on orthodontic tooth movement and interleukin 6 levels in gingival crevicular fluid in female subjects.Human RCT/DB split-mouthAlthough the mean rate of canine retraction was higher in the LG (0.013) than the CG (0.012) and there was definitely a tendency for more canine retraction in the LLLI, but the results failed to show any significant difference between the mean rate of canine retraction of both groups (P = 0.068). A paired t test showed that there was no significant difference in the mean concentration of IL-6 at various stages of the treatment between the groups during canine distalization (P > 0.05).
Nerves In vitro Primary cortical neurons Excitotoxicity Glutamate / NMDA / kainateHuang2014J BiophotonicsLow-level laser therapy (810 nm) protects primary cortical neurons against excitotoxicity in vitro.In vitroAlthough the prevention of cell death was modest but significant, LLLT (3 J/cm(2) delivered at 25 mW/cm(2) over 2 min) gave highly significant benefits in increasing ATP, raising mitochondrial membrane potential, reducing intracellular calcium concentrations, reducing oxidative stress and reducing nitric oxide. The action of LLLT in abrogating excitotoxicity may play a role in explaining its beneficial effects in diverse central nervous system pathologies.
Oral Tooth extraction Wisdom toothAlan2016Head Face MedEvaluation of the effects of the low-level laser therapy on swelling, pain, and trismus after removal of impacted lower third molar.Although there were decreasing trismus, swelling, and pain level, with this LLLT, there was significant difference only in the 7th day pain level in the laser group compared with the control group.
Tendons Achilles tendon Traumatized tendonsDemir2004Lasers Surg MedComparison of the effects of laser, ultrasound, and combined laser + ultrasound treatments in experimental tendon healing.RatAlthough US, L, and combined US + L treatments increased tendon healing biochemically and biomechanically more than the control groups, no statistically significant difference was found between them.
Oral Orthodontics Doshi-Mehta & Bhad-Patil2012Am J Orthod Dentofacial OrthopEfficacy of low-intensity laser therapy in reducing treatment time and orthodontic pain: a clinical investigation.HumanAn average increase of 30% in the rate of tooth movement was observed with the low-intensity laser therapy. Pain scores on the experimental sides were significantly lower compared with the control sides. Comment: An extremely low dose was used according to this paper. In my opinion, that low dose is unlikely to have biological effects. Note: A comment to this paper was published.
Circulation Red blood cells Linkova2008Bull Exp Biol MedEffect of low-intensity laser radiation of the red spectrum on some properties of erythrocytes in Wistar rats.An increase in the radiation power from 2.2 to 25 mW/cm2 was accompanied by a decrease in the erythrocyte sedimentation rate and an increase in erythrocyte filtration index. Radiation of 50 mW/cm2 induced abnormal erythrocyte aggregation. Increasing the time of irradiation at power intensity of 2.2 mW/cm2 did not potentiate its effect on the blood.
Eyes Prokofeva1996Vestn Oftalmol[Effects of low-intensity infrared laser irradiation on the eye (an experimental study)]. [Article in Russian]RabbitAn increase of intraocular pressure was recorded at a dose of 0.1 J/cm2 (4.5 min) and higher; morphological study showed dilated, well-filled and newly formed vessels in the ciliary body and iris, as well as edema and destruction of the external layers of the retina. Exposure to a dose of 0.05 J/cm2 and lower did not lead to destruction of ocular structures and increase of intraocular pressure. Comment: They reported harmful effects with a suspiciously low dose...
Nerves PNS Nissan1986Lasers Surg MedHeNe laser irradiation delivered transcutaneously: its effect on the sciatic nerve of rats.RatAn optimal range of energy between 3.5 and 7 J--associated with energy concentration of 4-10 J/cm2 delivered transcutaneously--was found to cause a significant increase in action potential in the sciatic nerve. The effect lasted for more than 8 months after the irradiation session.
Muscle Exercise Patrocinio2013Photomed Laser SurgEffect of low-level laser therapy (808 nm) in skeletal muscle after resistance exercise training in rats.RatAnalysis demonstrated that TGL demonstrated significantly reduced resting lactate level and decreased muscle glycogen depletion than the animals that were exercised only, and significantly increased the cross-section area of TA muscle fibers compared with thoseo in the other groups.
Nerves PNS Basford1993Lasers Surg MedEffects of 830 nm continuous wave laser diode irradiation on median nerve function in normal subjects.Human RCT/DBAnalysis of the results reveals that motor and sensory distal latencies were decreased in the treated limbs of the laser-treated group relative to the control group by 3-4% (P < .016 and .046, respectively, rank sum test). No significant differences in these quantities were found between the limbs within either group. Similarly, no alterations of action potential amplitudes, action potential areas, forearm conduction velocities, or skin temperatures were detected within or between the groups.
Eyes Light-induced damage LED phototherapyAhamed Basha2014Ann AnatProtective effect of light emitting diode phototherapy on fluorescent light induced retinal damage in Wistar strain albino rats.RatAnimals of the FL group showed a significant reduction in the outer nuclear layer thickness and cell count in addition to the total thickness of the retina. LL group which were exposed to 670 nm LED prior to exposure to fluorescent light showed a significant decrease in the degree of damage.
Nerves Diabetic neuropathy MIRE treatment with Anodyne LED pad deviceLavery2008Diabetes CareDoes anodyne light therapy improve peripheral neuropathy in diabetes? A double-blind, sham-controlled, randomized trial to evaluate monochromatic infrared photoenergy.Human RCT/DBAnodyne MIRE therapy was no more effective than sham therapy in the treatment of sensory neuropathy in individuals with diabetes.
Muscle Energy metabolism Larkin-Kaiser2015J Athl TrainNear-infrared light therapy to attenuate strength loss after strenuous resistance exercise.Human CrossoverApplied to skeletal muscle before resistance exercise, NIR light therapy effectively attenuated strength loss. Therefore, NIR light therapy may be a beneficial, noninvasive modality for improving muscle function during rehabilitation after musculoskeletal injury. However, future studies using higher treatment doses are warranted.
Dermatology Herpes zoster Postherpetic neuralgiaChen2016J Am Acad DermatolEarly application of low-level laser may reduce the incidence of postherpetic neuralgia (PHN).Human Retrospective dataApplying LLLT within the first 5 days of herpes zoster eruption significantly reduced the incidence of PHN. LLLT may have the potential to prevent PHN, but further well-designed randomized controlled trials are required.
Mechanisms Original research Isolated liver mitochondriaPassarella1988Biochem Biophys Res CommunIncrease in the ADP/ATP exchange in rat liver mitochondria irradiated in vitro by helium-neon laser.In vitroAs a result of experiments carried out with mitochondria loaded with either ATP or ADP, the increase in the activity of the ADP/ATP translocator is here proposed to depend on the increase in the electrochemical proton gradient which occurs owing to irradiation of mitochondria.
Mechanisms Original research Isolated hepatocytes Isolated liver mitochondriaGreco2001Lasers Surg MedHelium-Neon laser irradiation of hepatocytes can trigger increase of the mitochondrial membrane potential and can stimulate c-fos expression in a Ca2+-dependent manner.In vitroAs a result of irradiation, increase of the mitochondrial membrane potential was found to occur in irradiated hepatocytes both in the presence or in the absence of CaCl2. The hyperpolarization of the mitochondrial membrane is assumed to cause an increase in mitochondrial Ca2+ uptake that was measured in isolated mitochondria. Finally, an increase in c-fos expression was found in irradiated hepatocytes when incubated in the presence of CaCl2. This paper gives additional information on the mechanism by which He-Ne laser light, either directly or in a cascade-like effect dependent on increase in cell Ca2+, can cause cell stimulation.
Infections Staphylococcus Endophthalmitis LLLT vs dexamethasoneMa2012Lasers Med SciAntiinflammatory effect of low-level laser therapy on Staphylococcus epidermidis endophthalmitis in rabbits.RabbitAs an adjunct to vancomycin therapy to treat S. epidermidis endophthalmitis, LLLT has an antiinflammatory effect similar to that of dexamethasone.
Tendons Achilles tendon Collagenase-induced tendinitis PBM vs diclofenac Biphasic dose responseMarcos2011Photochem PhotobiolInfrared (810 nm) low-level laser therapy in rat achilles tendinitis: a consistent alternative to drugs.RatAs LLLT seems to act on inflammation through a selective inhibition of the COX-2 isoform in collagenase-induced tendinitis, LLLT may have potential to become a new and safer nondrug alternative to coxibs. We found that LLLT dose of 3 J significantly reduced inflammation through less COX-2-derived gene expression and PGE(2) production, and less edema formation compared to nonirradiated controls.
Pain Shoulder Physiotherapy + LLLTEslamian2012Lasers Med SciEffects of low-level laser therapy in combination with physiotherapy in the management of rotator cuff tendinitis.Human RCTAs one of physical modalities, gallium-arsenide low-power laser combined with conventional physiotherapy has superiority over routine physiotherapy from the view of decreasing pain and improving the patients function, but no additional advantages were detected in increasing shoulder joint range of motion in comparison to other physical agents.
Heart MI Lohr2009J Mol Cell CardiolEnhancement of nitric oxide release from nitrosyl hemoglobin and nitrosyl myoglobin by red/near infrared radiation: potential role in cardioprotection.RabbitAs shown in Figure 5B, exposure of the rabbit cardiac preparation to 60 mW/cm2 (11 J) of 670 nm light, in the absence of nitrite, at the time of reperfusion resulted in a significant reduction in infarct size whereas a lower power radiation (3 mW/cm2, 0.5J) was ineffective. Interestingly, when low dose radiation (3 mW/cm2) was combined with low-dose nitrite (0.4 mg/kg) a synergistic effect was observed suggesting that R/NIR is able to potentiate the cardioprotective effects of nitrite.
Brain Depression Major depression and anxietySchiffer2009Behav Brain FunctPsychological benefits 2 and 4 weeks after a single treatment with near infrared light to the forehead: a pilot study of 10 patients with major depression and anxiety.Human Pilot studyAt 2-weeks post treatment 6 of 10 patients had a remission (a score
Nerves PNS Khullar1995Eur J Oral SciThe effects of low level laser treatment on recovery of nerve conduction and motor function after compression injury in the rat sciatic nerve.RatAt 21 d post-injury, the laser-treated group had a significantly lower median SFI than the sham laser-treated group, indicating that the real laser treatment had improved functional recovery in the nerve. However, no differences were found between the evoked cAP parameters that were measured in the laser-treated and sham laser-treated groups. Histological examination reiterated the lack of difference between the two groups. Consequently, the effects of LLL on recovery must have occurred more peripherally to the point measured.
Toxins Snake venom Dourado2011Photochem PhotobiolLow-level laser therapy promotes vascular endothelial growth factor receptor-1 expression in endothelial and nonendothelial cells of mice gastrocnemius exposed to snake venom.MouseAt 3 days, LLLT increased angiogenesis (80%:HeNe vs 40%:GaAs), decreased neutrophils and increased proliferation of regenerating cells. However, after 21 days, myoregeneration observed in the [633nm] group appeared delayed compared with the V group. As LLLT improved revascularization, the suggestive delay in myoregeneration could be a dose-response inhibitory effect caused by multiple irradiations in myogenesis.
Circulation Aneurysm Ang-II-infused Apo-E(-/-) miceGavish2009Cardiovasc ResLow-level laser irradiation inhibits abdominal aortic aneurysm progression in apolipoprotein E-deficient mice.MouseAt 4 weeks, seven of 15 non-irradiated, but none of the 13 LLLI, mice had aneurysmal dilatation in the suprarenal aneurysm-prone segments that had progressed to >or=50% increase in maximal cross-sectional diameter (CSD) over baseline (P = 0.005 by Fishers exact test). The mean CSD of the suprarenal segments (normalized individually to inter-renal control segments) was also significantly lower in irradiated animals (LLLI vs. non-irradiated: 1.32 +/- 0.14 vs. 1.82 +/- 0.39, P = 0.0002 by unpaired, two-tailed t-test) with a 94% reduction in CSD at 4 weeks compared with baseline. M-mode ultrasound data showed that reduced radial wall velocity seen in non-treated was significantly attenuated in the LLLI mice, suggesting a substantial effect on arterial wall elasticity.
Systemic effects Corticosterone CytokinesLima2014Lasers Med SciEvaluation of corticosterone and IL-1β, IL-6, IL-10 and TNF-α expression after 670-nm laser photobiomodulation in rats.RatAt 6 h after surgery, a significant increase in corticosterone and a significant reduction in the levels of IL-1β and IL-6 in tissues of irradiated wounds were observed when compared to controls (p < 0.05). The levels of TNF-α and IL-10 expression were not significantly different between the groups at different time intervals. Thus, this study strongly suggests a systemic and local biomodulation of low-level laser therapy as indicated by the blood levels of corticosterone and the tissue expression of IL-1β and IL-6, respectively.
Immunity Lymphocytes Whole blood irradiationAl Musawi2017 epubLasers Med SciEffects of low-level laser irradiation on human blood lymphocytes in vitro.In vitroAt a wavelength of 589 nm and fluence of 72 J/cm2, irradiation of whole blood samples showed a significant increase in CD45 lymphocytes and natural killer (NK) (CD16, CD56) cells, but no significant changes in CD3 T lymphocytes, T-suppressor (CD3, CD8) cells, T-helper (CD3, CD4) cells, and CD19 B lymphocytes when compared with their non-irradiated counterparts. Our results clearly demonstrate that NK cell count is altered by irradiation, which ultimately affects the whole lymphocyte count significantly.
Intravascular LLLT Spinal cord injury patientsHuang2012Photomed Laser SurgEffects of intravascular laser irradiation of blood in mitochondria dysfunction and oxidative stress in adults with chronic spinal cord injury.Human RCT/SBAt day 15 of therapy, the study group revealed a significantly higher mitochondrial DNA (mtDNA) copy number, white blood cell adenosine triphosphate (WBC ATP) synthesis, and total antioxidant capacity (TAC) with significantly reduced malondialdehyde (MDA), than did the sham group. Star: The results are quite intriguing. This is interesting work.
Oral Orthodontics Garcia2016Lasers Med SciEffect of low-level laser therapy after rapid maxillary expansion: a clinical investigation.Human RCT/SBAt day 75 of the suture, the irradiated patients presented a greater percentage of approximate zones in the anterior (p = 0.008) and posterior (p = 0.001) superior suture-and less approximation in the posterior superior suture (p = 0.040)-than the placebo group. LLLT appears to stimulate the repair process during retention phase after RME.
Oral TMJ Carvalho2010Lasers Med SciWavelength effect in temporomandibular joint pain: a clinical experience.Human RetrospectiveAt the end of the 12 sessions the patients were again examined, and they scored their pain using the VAS. The results were statistically analyzed and showed that 64% of the patients were asymptomatic or had improved after treatment and that the association of both wavelengths was statistically significant (P = 0.02) in the asymptomatic group. It was concluded that the association of red and infrared (IR) laser light was effective in pain reduction on TMJ disorders of several origins.
Pain Back pain Vallone2014Photomed Laser SurgEffect of diode laser in the treatment of patients with nonspecific chronic low back pain: a randomized controlled trial.Human RCTAt the end of the 3 week period, the Laser+EX group showed a significantly greater decrease in pain than did the EX group. There was a significant difference between the two groups, with average Δ VAS scores of 3.96 (Laser+EX group) and 2.23 (EX group). Comment: One of the rare studies with a large spot size!
Oral Endodontics LED phototherapy LED and laserde Carvalho2015Lasers Med SciEffect of laser (λ 660 nm) and LED (λ 630 nm) photobiomodulation on formocresol-induced oral ulcers: a clinical and histological study on rodents.RatAt the end of the experimental period (11 days), there was no difference regarding to the size of the ulcers between the laser and LED groups, although there was a difference between the treated and untreated groups (p=0.0019). Comment: The difference between LLLT and LED groups, compared to the control group at the end of the study, are huge.
Nerves Diabetic neuropathy Khamseh2011Lasers Med SciDiabetic distal symmetric polyneuropathy: effect of low-intensity laser therapy.HumanAt the end of the study, the subjects showed a significant increase in neural potential amplitudes (p < 0.05). This study clearly demonstrated a significant positive effect of LILT on improvement of nerve conduction velocity on diabetic distal symmetric polyneuropathy (DSP). Comment: The parameters were insufficiently reported.
Skin Acne vulgaris Kwon2013Br J DermatolThe clinical and histological effect of home-use, combination blue-red LED phototherapy for mild-to-moderate acne vulgaris in Korean patients: a double-blind, randomized controlled trial.Human RCT/DBAt the final visit at 12 weeks, both inflammatory and noninflammatory acne lesions had decreased significantly, by 77% and 54%, respectively, in the treatment group. No significant difference was observed in the control group. In the treatment group, sebum output reduction, attenuated inflammatory cell infiltrations and a decreased size of the sebaceous gland were found. The immunostaining intensities for interleukin (IL)-8, IL-1α, matrix metalloproteinase-9, toll-like receptor-2, nuclear factor-κB, insulin-like growth factor-1 receptor and sterol response element binding protein (SREBP)-1 were reduced concomitantly. Messenger RNA expression of SREBP-1c was also decreased. No severe adverse reactions were reported.
Oral Periodontium Qadri2007Lasers Med SciThe importance of coherence length in laser phototherapy of gingival inflammation: a pilot study.Human Pilot studyAt the follow up examination, all clinical parameters had improved significantly in both groups. A more pronounced decrease of clinical inflammation was observed after HeNe treatment.
Cells Energy metabolism Human neural progenitor (NHNP) cellsOron2007Photomed Laser SurgGa-As (808 nm) laser irradiation enhances ATP production in human neuronal cells in culture.In vitroATP was determined at 10 min after laser application. The quantity of ATP in laser-treated cells was 7513 +/- 970 units, which was significantly higher (p < 0.05) than the non-treated cells, which comprised 3808 +/- 539 ATP units.
Nerves Diabetic neuropathy MIRE treatment with Anodyne LED pad deviceLeonard2004Diabetes CareRestoration of sensation, reduced pain, and improved balance in subjects with diabetic peripheral neuropathy: a double-blind, randomized, placebo-controlled study with monochromatic near-infrared treatment.Human RCT/DBATS treatments improve sensation in the feet of subjects with DPN, improve balance, and reduce pain.
Fertility, genitals, etc. Sperm motility Dog spermCorral-Baqués2005Lasers Med SciEffect of 655-nm diode laser on dog sperm motility.In vitroAverage path velocity (VAP), linear coefficient (Lin) and beat cross frequency (BCF) were statistically and significantly different when compared to the control. The functional tests also showed a significant difference. At these parameters, the 655-nm continuous-wave diode laser improves the speed and linear coefficient of the sperm.
Oral TMJ Cavalcanti2016 epubPhotomed Laser SurgComparative Study of the Physiotherapeutic and Drug Protocol and Low-Level Laser Irradiation in the Treatment of Pain Associated With Temporomandibular Dysfunction.Based on obtained data, we concluded that, compared to PDP, LLL treatment is effective to control pain associated with TMD.
Dermatology Herpes labialis Eduardo Cde2012Lasers Med SciPrevention of recurrent herpes labialis outbreaks through low-intensity laser therapy: a clinical protocol with 3-year follow-up.Case seriesBased on the outcomes observed in this study, it is possible to conclude that the preventive protocol proposed may represent an alternative treatment for patients presenting recurrent herpes labialis infection.
Oral Oral mucositis LLLT vs methylene blue + LLLTMedeiros Filho2017 epubPhotodiagnosis Photodyn TherLaser and photochemotherapy for the treatment of oral mucositis in young patients: randomized clinical trial.Human RCTBased on the present findings, PCT+LLLT had a greater therapeutic effect in comparison to LLLT alone regarding the reduction in the degree of severity of chemotherapy-induced oral mucositis.
Bone Bone repair Barbosa2014Acta Ortop BrasLaser therapy in bone repair in rats: analysis of bone optical density.RatBased on the radiographic findings, G (830nm) showed more complete bone regeneration, as shown in the gray shades of the images.
Stevens-Johnson syndrome Simões2011Photomed Laser SurgLaser phototherapy for Stevens-Johnson syndrome: a case report.Case reportBecause of the lack of progress of the patient, the LPT was selected. By 6 days after his initial session of LPT, most of the patients intraoral lesions had disappeared, and the few that remained were painless; the patient was able to eat solid food by himself and was removed from the ICU. Ten sessions of LPT were conducted in the hospital.
Insect health Bumblebee Imidaclopride toxicityPowner2016PLoS OneImproving Mitochondrial Function Protects Bumblebees from Neonicotinoid Pesticides.BumblebeeBees exposed to insecticide and daily to 670nm light showed corrected ATP levels and significantly improved mobility allowing them to feed. Physiological recordings from eyes revealed that light exposure corrected deficits induced by the pesticide. Overall, death rates in bees exposed to insecticide but also given 670nm light were indistinguishable from controls. Treatment with 670nm on control bees also resulted in a significant improvement in survival over controls (P<0.01), similar to data from fruit flies exposed to this light [15] Hence, we show that deep red light exposure that improves mitochondrial function, reverses the sensory and motor deficits induced by Imidacloprid.
Oral Oral mucositis Patients with head/neck cancerOton-Leite2013Spec Care DentistEffect of low level laser therapy in the reduction of oral complications in patients with cancer of the head and neck submitted to radiotherapy.Human RCTBetter outcomes were observed in the laser group when compared with the control in the follow-up sessions, indicating lower degrees of oral mucositis, pain and higher salivary flow (p < .05).
Tendons Achilles tendon Collagenase-induced tendinitis PBM vs diclofenacMarcos2012J Orthop ResLow-level laser therapy in collagenase-induced Achilles tendinitis in rats: analyses of biochemical and biomechanical aspects.RatBiomechanical properties were preserved in the laser-treated groups when compared to collagenase and diclofenac groups. We conclude that LLLT was able to reduce tendon inflammation and to preserve tendon resistance and elasticity.
Oral Endodontics Montoro2014Int Endod JInfrared LED irradiation photobiomodulation of oxidative stress in human dental pulp cells.In vitroBiomodulation of oxidative stress of [human dental pulp cells] can be achieved by irradiation with a single dose of infrared LED. Within the range investigated, 15 J cm(-2) resulted in the least production of NO.
Skin Acne vulgaris LED phototherapy (w/ blue light)Lee2007Lasers Surg MedBlue and red light combination LED phototherapy for acne vulgaris in patients with skin phototype IV.HumanBlue and red light combination LED phototherapy is an effective, safe and non-painful treatment for mild to moderately severe acne vulgaris, particularly for papulopustular acne lesions.
Pain Hyperalgesia Nadur-Andrade2014Photochem PhotobiolAnalgesic Effect of Light-Emitting Diode (LED) Therapy at Wavelengths of 635 and 945 nm on Bothrops moojeni Venom-Induced Hyperalgesia.MouseBoth 635 nm and 945 nm LED inhibited mechanical allodynia and hyperalgesia of mice alone or in combination with antivenom treatment, even when the symptoms were already present.
Oral Aphthous stomatitis Picasso laserJijin2016Oral Surg Oral Med Oral Pathol Oral RadiolLow-level laser therapy versus 5% amlexanox: a comparison of treatment effects in a cohort of patients with minor aphthous ulcers.Human comparison trialBoth amlexanox and LLLT were equally effective in relieving pain associated with minor aphthous stomatitis. Both groups showed significant reduction in ulcer sizes and in pain scores.
Hearing Hearing loss Noise-induced hearing lossLee2016PeerJSimultaneous bilateral laser therapy accelerates recovery after noise-induced hearing loss in a rat model.RatBoth bilateral and unilateral laser therapy decreased the hearing threshold after noise overstimulation in the rat model. The bilateral laser therapy group showed faster functional recovery at all tested frequencies compared with the unilateral laser therapy group. Star: Parameters were well reported in a table.
Mechanisms Original research Isolated hepatocytes CoherenceVacca1996J Photochem Photobiol BIncrease in cytosolic and mitochondrial protein synthesis in rat hepatocytes irradiated in vitro by He-Ne laser.In vitroBoth cytosolic and mitochondrial protein synthesis increased as a result of irradiation, as demonstrated by the measurement of hepatocytes previously treated with chloramphenicol and cycloheximide respectively. An initial investigation showed that stimulation of protein synthesis also occurred in hepatocytes irradiated with a non-coherent radiation source (fluence, 0.24 J cm(-2)).
Joints Osteoarthritis Papain-induced joint inflammation Biphasic dose responsedos Santos2014Lasers Med SciComparative analysis of two low-level laser doses on the expression of inflammatory mediators and on neutrophils and macrophages in acute joint inflammation.RatBoth laser modalities were efficient in reducing cellular inflammation and decreasing the expression of IL-1β and IL-6. However, the 2-J treatment led to more reduction in TNF-α than the 4-J treatment. A single application of LLLT with 2 J was more efficient in modulating inflammatory mediators and inflammatory cells.
Immunity Macrophage-like cells Fernandes2015J Photochem Photobiol BPhotobiomodulation with 660-nm and 780-nm laser on activated J774 macrophage-like cells: Effect on M1 inflammatory markers.In vitroBoth lasers were able to reduce TNF-α and iNOS expression, and TNF-α and COX-2 production, although the parameters used for 780 nm laser provided an additional decrease. 660 nm laser parameters resulted in an up-regulation of IL-6 expression and production. These findings imply a distinct, time-dependent modulation by the two different sets of laser parameters, suggesting that the best modulation may involve more than one combination of parameters.
Safety of LLLT Ilic2006Photomed Laser SurgEffects of power densities, continuous and pulse frequencies, and number of sessions of low-level laser therapy on intact rat brain.RatBoth the scores from standard neurological tests and the histopathological examination indicated that there was no long-term difference between laser-treated and control groups up to 70 days post-treatment. The only rats showing an adverse neurological effect were those in the 750 mW/cm2 (about 100-fold optimal dose), CW mode group. Long-term safety tests lasting 30 and 70 days at optimal 10x and 100x doses, as well as at multiple doses at the same power densities, indicate that the tested laser energy doses are safe under this treatment regime.
Muscle Exercise Assis2015Braz J Phys TherEffect of low-level laser therapy (808 nm) on skeletal muscle after endurance exercise training in rats.RatBoth trained groups showed significant increase in speed compared to the CG. The TLG demonstrated a significantly reduced lactate level, increased tibialis anterior (TA) fiber cross-section area, and decreased TA fiber density.
Oral Endodontics Moreira2016J Photochem Photobiol BIn vivo experimental model of orthotopic dental pulp regeneration under the influence of photobiomodulation therapy.RatBriefly, this tissue-engineered orthotopic model of dental pulp regeneration consisted of instrumentation of the dentinal walls with removal of dental pulp tissue from the mesial root canal of the first molar of rats, followed by treatment of the root canal walls with an acidic solution to release growth factors and induction of bleeding into the canal to create a blood clot (i.e., natural scaffold) rich in endogenous stem cells, prior to the laser PBM therapy application. No tissue formation was observed in any specimen of the Control group (n = 12). In three out of the 11 teeth composing the PBM group, the mesial root canal was filled with an immature connective tissue (Fig. 2). This tissue was composed of fewer and thinner collagen fibers than the originally preserved dental pulp of the distal root of the same molar (Fig. 2A and B). A layer of cells in intimate contact with the dentin wall was observed to exhibit cytoplasmic extensions into the dentinal tubules (Fig. 2C). Immunohistochemical analysis of the tissue formed inside the experimental root canal showed an odontoblast-like cell layer labeled with anti-HSP-25 (Fig. 3A), blood vessels exhibiting SMA-positive cells in their walls (Fig. 3B), S-100-positive cells underneath the odontoblast-like cell layer (Fig. 3C) and a few STRO-1-positive cells in perivascular niches (Fig. 3D). Most importantly, our results corroborate the hypothesis that PBM therapy may be an adjunctive therapy that is able to improve dental pulp tissue regeneration.
Oral Burning mouth syndrome Kato2010Photomed Laser SurgLow-level laser therapy in burning mouth syndrome patients: a pilot study.Human Pilot studyBurning intensity at the end of the laser therapy was statistically lower than at the beginning (p < 0.01). Patients reported an 80.4% reduction in the intensity of symptoms after laser treatment. There was no statistical difference between the end of the treatment and the 6-week follow-up, except for the tongue site.
Oral Periodontium LED phototherapyChang2015Lasers Med SciControlling periodontal bone levels with multiple LED irradiations.RatBy day 7, PBL was significantly reduced (p < 0.05), with significantly reduced inflammation (p < 0.05) and gingival hyperplasia (p < 0.001), in the animals receiving three irradiations per week. At day 14, the reduction in gingival hyperplasia was still significant (p < 0.05), and collagen matrix deposition and realignment appeared to be accelerated in the animals receiving three irradiations per week, despite a lack of significant difference in PBL. The treatment regimen receiving three LED light irradiations per week apparently extended the effects in reducing PBL and inflammation to 7 days.
Diabetes mellitus Ulcers and wounds LED phototherapyMinatel2009Lasers Surg MedPhototherapy promotes healing of chronic diabetic leg ulcers that failed to respond to other therapies.Human RCT/DBBy day 90, 58.3% of group two ulcers had healed fully and 75% had achieved 90-100% healing. In contrast, only one placebo treated ulcer healed fully by day 90; no other ulcer attained > or =90% healing. [Also see additional info]
Hair Alopecia, non-inflammatoryOlivieri2015Vet DermatolEfficacy of low-level laser therapy on hair regrowth in dogs with noninflammatory alopecia: a pilot study.DogBy morphometry, the area occupied by hair follicles was 18% in the treated sample and 11% in the untreated one (11%) Haired follicles were (per area) 93% in the treated sample and only 9% in the control sample. Comment: Article has some nice photographs of the LLLT device/treatment and the effects.
Mechanisms Original research Ball2011J Photochem Photobiol BLow intensity light stimulates nitrite-dependent nitric oxide synthesis but not oxygen consumption by cytochrome c oxidase: Implications for phototherapy.In vitroBy using a series of bandpass filters and light emitting devices (LEDs) we have determined that maximal stimulation of Cco/NO activity is achieved by exposure to light whose central wavelength is 590 ± 14 nm. This wavelength of light stimulates Cco/NO synthesis at physiological nitrite concentrations. These findings raise the interesting possibility that low intensity light exerts a beneficial effect on cells and tissues by increasing NO synthesis catalyzed by Cco and offer a new explanation for the increase in NO bioavailability experienced by tissue exposed to light.
Oral Aphthous stomatitis CO2 laserColvard & Kuo1991J Am Dent AssocManaging aphthous ulcers: laser treatment applied.Human Case report (?)Carbon dioxide laser therapy was used to treat a minor form of the ulcer (canker sore); the laser therapy reduced or eliminated the pain and inflammation with normal wound healing.
Heart MI MI LLLT? (λ = 1320 nm)Whittaker (Peter)1999Lasers Surg MedLaser-mediated reversal of cardiac expansion after myocardial infarction.RatCavity volume was reduced by laser treatment (0.72 +/- 0.07 ml vs. 0.54 +/- 0.05 ml; P= 0.044). In addition, treatment resulted in thicker scars, a leftward shift of the hearts electrical axis, and straightening of collagen fibers.
Pain Neuropathic Chronic constriction injuryJanzadeh2016Lasers Med SciPhotobiomodulation therapy reduces apoptotic factors and increases glutathione levels in a neuropathic pain model.RatCCI decreased the pain threshold, 2-week photobiomodulation therapy significantly increased mechanical and thermal threshold, decreased P2X3 expression (p < 0.001), and increased bcl2 expression (p < 0.01), but it was not effective on the Bax expression. We speculated that although photobiomodulation therapy increased ROS generation, it increased antioxidants such as GSH.
Pain Neuropathic Chronic constriction injuryMasoumipoor2014Lasers Med SciEffects of 660- and 980-nm low-level laser therapy on neuropathic pain relief following chronic constriction injury in rat sciatic nerve.RatCCI decreased the pain threshold, whereas both wavelengths of LLLT for 2 weeks increased mechanical and thermal threshold significantly. Based on our findings, the laser with a 660-nm wavelength had better therapeutic effects than the laser with a 980-nm wavelength, so the former one may be used for clinical application in neuropathic cases; however, it needs more future studies.
Autoimmunity Multiple sclerosis Experimental autoimmune encephalomyelitis LED phototherapyMuili2013PLoS OnePhotobiomodulation induced by 670 nm light ameliorates MOG35-55 induced EAE in female C57BL/6 mice: a role for remediation of nitrosative stress.Mouse Cell culture experiments demonstrated that 670 nm light-mediated photobiomodulation attenuated antigen-specific nitric oxide production by heterogenous lymphocyte populations isolated from MOG immunized mice. Experiments in the EAE model demonstrated down-regulation of inducible nitric oxide synthase (iNOS) gene expression in the spinal cords of mice with EAE over the course of disease, compared to sham treated animals. Animals receiving 670 nm light treatment also exhibited up-regulation of the Bcl-2 anti-apoptosis gene, an increased Bcl-2:Bax ratio, and reduced apoptosis within the spinal cord of animals over the course of disease. 670 nm light therapy failed to ameliorate MOG-induced EAE in mice deficient in iNOS, confirming a role for remediation of nitrosative stress in the amelioration of MOG-induced EAE by 670 nm mediated photobiomodulation.
Bone In vitro Ülker2016Lasers Med SciPolychromatic light-induced osteogenic activity in 2D and 3D cultures.In vitroCell culture studies under static conditions indicated that polychromatic light significantly stimulated bone nodule formation via the prolonged cell survival and stimulated differentiation of MC3T3-E1 preosteoblastic cells in both TCPS and chitosan scaffold groups.
Stem cells & regeneration Mvula & Abrahamse2016Photomed Laser SurgDifferentiation Potential of Adipose-Derived Stem Cells When Cocultured with Smooth Muscle Cells, and the Role of Low-Intensity Laser Irradiation.Cell viability and proliferation increased significantly in the cocultured groups that were exposed to LILI alone, as well as in combination with growth factors. Further, there was a significant decrease in the expression of stem cell markers with a concomitant increase in SMC markers.
Oncology Tumor cells Isolated lung cancer stem cellsCrous & Abrahamse2016Photomed Laser SurgLow-Intensity Laser Irradiation at 636 nm Induces Increased Viability and Proliferation in Isolated Lung Cancer Stem Cells.In vitroCellular morphology indicated an increase in cell density caused by cell proliferation over time. Biostimulatory effects were achieved in lung CSCs when examining viability and proliferation. It should, therefore, be noted that a low wavelength of 636 nm at various fluences induces biostimulation, which may have detrimental effects when using LILI as a form of regeneration.
Cells Proliferation Human HEP-2 Murine L-929Brondon2005Lasers Surg MedA study of the effects of phototherapy dose interval on photobiomodulation of cell cultures.In vitroCellular response to dose frequency varies. More frequent treatments (2/24 hours) increased metabolism and proliferation in both cell lines. Further investigation of dose fractionation in phototherapy is warranted.
Brain Cognitive performance LED phototherapy LED array (784)Grover2016 epubPhotomed Laser SurgAcute Effects of Near Infrared Light Therapy on Brain State in Healthy Subjects as Quantified by qEEG Measures.HumanChange in reaction time significantly differed between treated and control, with a mean of 23.8 msec improvement compared with controls (p = 0.035). Amplitude increased an average of 0.81 μV in treatment versus 0.22 μV in controls and did not reach significance. The data suggest that NIR light may have an acute effect on reaction time and amplitude in certain subject subsets. There were no adverse events registered across the 31 subjects in the treatment group, nor in the 18 evaluable control group subjects.
Joints Haemophilic arthropathy El-Shamy & Abdelaal2016 epubDisabil RehabilEfficacy of pulsed high-intensity laser therapy on pain, functional capacity, and gait in children with haemophilic arthropathy.Human RCTChildren in the laser group showed significant improvement in pain, functional capacity, and gait parameters compared to those in the placebo group (p < 0.05). Comment 1: Parameters were somewhat poorly reported. Even wavelength was not mentioned. Comment 2: However, results are encouraging. This isnt the first time that Egyptian researchers report very good results for the diseases they are treating with HILT.
Brain Alzheimers Disease Grillo2013J Photochem Photobiol BNon-invasive infra-red therapy (1072 nm) reduces β-amyloid protein levels in the brain of an Alzheimers disease mouse model, TASTPM.MouseChronic IR1072 treatment of female TASTPM mice elicited significant increases in HSP60, 70 and 105 and phosphorylated-HSP27 (P-HSP27) (50-139%), together with a concomitant profound decrease in αB-crystallin, APP, tau-P, Aβ1-40 and Aβ1-42 (43-81%) protein levels at 7 months of age. Furthermore, IR1072 treatment elicited a modest, but significant, reduction in Aβ1-42 plaques in the cerebral cortex. IR1072 treatment provides a novel non-invasive and safe way to upregulate a panel of stress response proteins in the brain, known to both reduce protein aggregation and neuronal apoptosis. This approach recently entered clinical trials for AD in the USA, and may provide a novel disease modifying therapy for a range of neuropathologies.
Joints Rheumatoid arthritis Collagen-induced RAZhang2011Laser TherReduction of CXCR4 expression in Rheumatoid Arthritis Rat Joints by low level diode laser irradiation.RatCIA significantly increased swelling in the rat hind-paw and LLLI reduced the CIA-induced swelling. Decreased CXCR4 expression may be one of the mechanisms in LLLI-mediated reduction of RA inflammation.
Skin Psoriasis Recalcitrant psoriasisAblon G2010Photomed Laser SurgCombination 830-nm and 633-nm light-emitting diode phototherapy shows promise in the treatment of recalcitrant psoriasis: preliminary findings.Human Case seriesClearance rates at the end of the follow-up period ranged from 60% to 100%. Satisfaction was universally very high.
Oral Osteonecrosis Vescovi2012Photomed Laser SurgEarly surgical laser-assisted management of bisphosphonate-related osteonecrosis of the jaws (BRONJ): a retrospective analysis of 101 treated sites with long-term follow-up.Human RetrospectiveClinical improvement was achieved in 3 out of 12 (25%) BRONJ sites in G1. Sites if G2 with an improvement were 18 out of 27 (66%). (...) For sites in G4, a clinical improvement was recorded in 40 out of 45 cases (89%). G1 = medical therapy G2 = LLLT G3 = medical + surgical + LLLT
Oral Oral mucositis Intraoral + Extraoral Pediatric patients undergoing HSCTSoto2015Photomed Laser SurgPilot study on the efficacy of combined intraoral and extraoral low-level laser therapy for prevention of oral mucositis in pediatric patients undergoing hematopoietic stem cell transplantation.Human RCTClinical mucositis scores were significantly lower in the LLLT group than in the control group (p = 0.004). Incidence of ulcerative oral mucositis was also significantly lower in the LLLT group (p = 0.027). Functional limitation associated with diet/swallowing was less severe in the LLLT group; however, this was not statistically significant. Star: Nice study setting. A well-written paper.
Cells Proliferation Human fibroblasts Biphasic dose responsevan Breugel1992Lasers Surg MedPower density and exposure time of He-Ne laser irradiation are more important than total energy dose in photo-biomodulation of human fibroblasts in vitro.In vitroCollagen type I production (as determined by an ELISA) was affected in the opposite direction to cell proliferation: when the cell proliferation was increased, collagen type I production was decreased. Both stimulation and inhibition of the observed cell properties can be obtained with the same laser on the same cells. Comment: Increased proliferation was noted in only one of the four groups studied.
Oncology Tumor cells LLLT + melatonin treatmentAkbarzadeh2016Lasers Med SciEffects of combination of melatonin and laser irradiation on ovarian cancer cells and endothelial lineage viability.In vitroCombination treatment of both cell lines caused a marked increase in apoptosis/necrosis rate, reactive oxygen species generation, and heat shock protein 70 expression compared to incubation of the cells with each agent alone (p < 0.05)
Nerves In vitro Biphasic dose response (?)Ignatov2005Neurosci Behav PhysiolEffects of helium-neon laser irradiation and local anesthetics on potassium channels in pond snail neurons.In vitroCombined application of laser irradiation at a dose of 0.7 x 10(-3) J increased the blocking effect of 10 microM bupivacaine on the slow potassium current, while an irradiation dose of 0.7 x 10(-4) J weakened the effect of bupivacaine.
Wound healing Incisions LED array (4 red + 13 blue) LED phototherapyFigurová2016Photomed Laser SurgHistological Assessment of a Combined Low-Level Laser/Light-Emitting Diode Therapy (685 nm/470 nm) for Sutured Skin Incisions in a Porcine Model: A Short Report.Pig (minipig)Combined red and blue PBM accelerated the process of re-epithelization and formation of cross-linked collagen fibers compared with sham irradiated control wounds. Our results demonstrate that the current dose of combined red and blue PBM improves the healing of sutured skin incisions in minipigs.
Skin Cell protection Fibroblasts KeratinocytesChabert2015Skin Res TechnolEvaluation of light-emitting diodes (LED) effect on skin biology (in vitro study).In vitroCombined, the LED wavelengths could improve in vitro the cell shape, the cell proliferation, and the level of major proteins involved in the healing process.
Muscle Exercise De Marchi2012Lasers Med SciLow-level laser therapy (LLLT) in human progressive-intensity running: effects on exercise performance, skeletal muscle status, and oxidative stress.Human RCT/DB CrossoverCompared to placebo, active LLLT significantly increased exercise performance (VO(2 max) p = 0.01; time to exhaustion, p = 0.04) without changing the aerobic and anaerobic thresholds. LLLT also decreased post-exercise lipid (p = 0.0001) and protein (p = 0.0230) damages, as well as the activities of SOD (p = 0.0034), CK (p = 0.0001) and LDH (p = 0.0001) enzymes. LLLT application was not able to modulate CAT activity. The use of LLLT before progressive-intensity running exercise increases exercise performance, decreases exercise-induced oxidative stress and muscle damage, suggesting that the modulation of the redox system by LLLT could be related to the delay in skeletal muscle fatigue observed after the use of LLLT.
Muscle Exercise Leal Junior2008Photomed Laser SurgEffect of 655-nm low-level laser therapy on exercise-induced skeletal muscle fatigue in humans.Human RCT/DBCompared to the first session (on day 1), the mean number of repetitions increased significantly by 8.5 repetitions (+/- 1.9) in the active LLLT group at the second session (on day 8), while in the placebo LLLT group the increase was only 2.7 repetitions (+/- 2.9) (p = 0.0001).
Muscle Exercise LED phototherapyFerraresi2016Am J Phys Med RehabilEffects of Light-Emitting Diode Therapy on Muscle Hypertrophy, Gene Expression, Performance, Damage, and Delayed-Onset Muscle Soreness: Case-control Study with a Pair of Identical Twins.Human RCT Twin studyCompared with placebo, LEDT increased the maximal load in exercise and reduced fatigue, creatine kinase, and visual analog scale. Gene expression analyses showed decreases in markers of inflammation (interleukin 1β) and muscle atrophy (myostatin) with LEDT. Protein synthesis (mammalian target of rapamycin) and oxidative stress defense (SOD2 [mitochondrial superoxide dismutase]) were up-regulated with LEDT, together with increases in thigh muscle hypertrophy. Light-emitting diode therapy can be useful to reduce muscle damage, pain, and atrophy, as well as to increase muscle mass, recovery, and athletic performance in rehabilitation programs and sports medicine.
Nerves PNS Zhang2010SynapseEffects of 660-nm gallium-aluminum-arsenide low-energy laser on nerve regeneration after acellular nerve allograft in rats.RatCompared with the ARSN group, laser therapy significantly increased nerve conduction velocity, restoration rate of tibialis anterior wet muscle weight, myelinated nerve number, and CGRP protein and mRNA expression of the L(4) spinal cord at the injury site. Comment: Irradiation parameters were insufficiently reported.
Nerves PNS Cidral-Filho2013Eur J PainLight-emitting diode therapy induces analgesia and decreases spinal cord and sciatic nerve tumour necrosis factor-α levels after sciatic nerve crush in mice.MouseCompared with the SNC group, LEDT reduced mechanical hypersensitivity but not cold hypersensitivity which is induced by SNC, decreased spinal cord and sciatic nerve levels of tumour necrosis factor alpha (TNF-α) but did not alter interleukin (IL)-1β and IL-10 levels, and finally, failed to accelerate motor functional recovery and morphological nerve regeneration.
Gastroenterology Atrophic gastritis Biphasic dose responseYang2005Sheng Wu Yi Xue Gong Cheng Xue Za Zhi[Effects of He-Ne laser on gastric mucosa in rat with chronic atrophic gastritis]. [Article in Chinese]RatCompared with untreated group, the gastric mucosa of 3.36J x cm(-2) He-Ne laser group was significantly thicker (P < 0.01), the inflammatory cells of gastric mucosa were decreased (P < 0.05), the morphology, structure and volume of the cells were restored or nearly normal and the expressions of cyclinD1 were higher (P < 0.05). In a word, small dose He-Ne laser (3.36 J x cm(-2)) has a good adjuvant therapeutic effect on rats CAG.
Oral Burning mouth syndrome LLLT vs clonazepamArduino2016Lasers Med SciA randomized pilot study to assess the safety and the value of low-level laser therapy versus clonazepam in patients with burning mouth syndrome.Human RCT ComparisonComparing the two groups, LLLT appeared to be superior in improving pain perception, but statistically only at 8 weeks after the end of the protocol proposed (P = 0.026).
Oral Periodontium Kumaresan2016Eur J DentGingival crevicular fluid periostin levels in chronic periodontitis patients following nonsurgical periodontal treatment with low-level laser therapy.Human ControlledComparison of mean periostin levels between both the treatment groups showed a significant increase in LLLT group than RSD at the 3rd month (P < 0.05). Within the limitations of the present study, LLLT application was found to have additional benefits over RSD with respect to clinical periodontal parameters and GCF periostin levels. Moreover, periostin may be used as a possible biomarker to evaluate the outcome following NSPT.
Nerves PNS AxonotmesisGomes2012Photomed Laser SurgThe brain-derived neurotrophic factor, nerve growth factor, neurotrophin-3, and induced nitric oxide synthase expressions after low-level laser therapy in an axonotmesis experimental model.RatComparisons between groups showed that HeNe laser increased the mRNA expression of both BDNF and NGF factors after 14 days of LLLT, with peak expression at the 21st day. Increase in NT-3 mRNA expression was not observed. In addition, HeNe laser produced iNOS expression reduction, which played an important role in the inflammatory process.
Oral Aphthous stomatitis Aggarwal2014J Clin Diagn ResEfficacy of low-level laser therapy in treatment of recurrent aphthous ulcers - a sham controlled, split mouth follow up study.Human RCT (?)Complete resolution of the ulcers in the active group was 3.05 ± 1.10 days as compared to 8.90 ± 2.45 days in the sham control group. Immediately, post the LLLT application, complete pain relief was observed in 28 of the 30 patients of the active group.
Bone Bone repair Ovariectomized rats Pulsed LLLTMohsenifar2016Lasers Med SciEvaluation of the effects of pulsed wave LLLT on tibial diaphysis in two rat models of experimental osteoporosis, as examined by stereological and real-time PCR gene expression analyses.RatConcurrent treatments of PW LLLT and alendronate produced the same effect on osteoporotic bone. Since the PW LLLT has osteogenic effects, different parameters should be investigated to verify whether an appropriate PW LLLT protocol in combination with a proper(s) anti osteoporotic agent(s) might reverse the detrimental effects of OP.
Muscle Muscle injury (Sarcopenia)Pertille2012Rev Bras FisioterEvaluation of muscle regeneration in aged animals after treatment with low-level laser therapy.RatConsidering the morphological and molecular analyzes performed, as well as the parameters used, it may be concluded that low-level laser therapy affects muscle regeneration of aged animals through its anti-inflammatory effects alone, as the results did not demonstrate an effect on the contents of the proteins studied. Comment: The results suggest that LLLT increased the recovery of cross sectional area of muscles quite markedly, but the authors claim there was no difference. Maybe its a matter of statistical significance.
Oral Tooth extraction Freitas2001Braz Dent JAssessment of anti-inflammatory effect of 830nm laser light using C-reactive protein levels.HumanCRP values were more symmetric and better distributed for the irradiated group (0.320 mg/dl) than for the control ( 48 h after surgery, however there was no statistically significant difference. After 72 h, both groups had statistically similar CRP levels (0.272 and 0.608 mg/dl), because of the normal tendency of decreasing CRP levels.
Muscle Muscle injury Muscle regenerationMorais2016Lasers Med SciStrength training prior to muscle injury potentiates low-level laser therapy (LLLT)-induced muscle regeneration.RatCryolesion induced massive muscle degeneration associated with inflammatory infiltrate. Prior ST improved skeletal regeneration 14-days after cryolesion and potentiated the regenerative response to LLLT.
Cosmetic medicine Body contouring LAPEX 2000 LipoLaserCaruso-Davis2011Obes SurgEfficacy of low-level laser therapy for body contouring and spot fat reduction.Human RCTCumulative girth loss after 4 weeks was −2.15 cm (−0.78 ± 2.82 vs. 1.35 ± 2.64 cm for the control group,p < 0.05). A blinded evaluation of standardized pictures showed statistically significant cosmetic improvement after 4 weeks of laser treatment.
Mechanisms Original research Pastore2000Int J Radiol BiolSpecific helium-neon laser sensitivity of the purified cytochrome c oxidase.In vitroCytochrome c oxidation catalysed by COX was affected by He-Ne laser irradiation of the purified enzyme. This study shows that purified COX is a specific target of He-Ne laser light; therefore, COX may be considered to be a mitochondrial photo-acceptor.
Eyes Diabetic macular edemaTang2014Br J OphthalmolPhotobiomodulation in the treatment of patients with non-center-involving diabetic macular oedema.Human Case seriesDaily PBM treatment for only 80 s per treatment twice daily caused a significant reduction in focal retinal thickening in all 4 treated eyes. No adverse effects attributable to therapy were noted by the patients or study investigators during the study period.
Gene expression WavelengthFonseca2014Laser Phys LettLow-intensity red and infrared lasers on XPA and XPC gene expressionIn vitroData obtained show that laser radiation alters the expression of XPA and XPC mRNA differently in skin and muscle tissue of Wistar rats, depending on physical (fluence and wavelength) and biological (tissue) parameters. Laser light could modify expression of genes related to the nucleotide excision repair pathway at fluences and wavelengths used in clinical protocols.
Immunity Vilela2012J Photochem Photobiol BInfluence of the HPA axis on the inflammatory response in cutaneous wounds with the use of 670-nm laser photobiomodulation.RatDecreases in the number of CD45-positive inflammatory cells and in the total numbers of CD8- and CD45-positive cells were observed in histological sections of adrenalectomized animals subjected to laser biomodulation at 24h. Similar results were observed for distribution of total lymphocytes in blood (p<0.05). The action of 670 nm laser does not depend exclusively on HPA axis. It is believed that corticosteroid-promoting enzymes liberated in non-adrenal tissues may influence immune response under the influence of this type of phototherapy.
Nerves PNS Wavelength comparisonBarbosa2010Lasers Med SciComparative effects of wavelengths of low-power laser in regeneration of sciatic nerve in rats following crushing lesion.RatDifferences in SFI were found between group 660 nm and the other ones at the 14th day. One can observe that laser application at 660 nm with the parameters and methods utilised was effective in promoting early functional recovery, as indicated by the SFI, over the period evaluated. Comment: 830nm was not effective in this study. In the 660nm group, the SFI benefit was not very large.
Oral Tooth extraction Hamad2016J Maxillofac Oral SurgEffect of Diode Laser on Healing of Tooth Extraction Socket: An Experimental Study in Rabbits.RabbitDiode laser application to tooth extraction socket has a positive effect on bone formation.
Pain Nociception Tsuchiya1994Brain Res BullLaser irradiation abates neuronal responses to nociceptive stimulation of rat-paw skin.RatDiode laser irradiation (830 nm, 40 mW, 3 min, continuous wave) of the saphenous nerve exposed from the muscle of the lower leg significantly inhibited neuronal discharges elicited by pinch (68.4 +/- 6.5%), cold (45.4 +/- 9.2%), and heat stimulation (49.2 +/- 11.3%). Neuronal discharges induced by brush stimulation (104.3 +/- 4.7%) were not affected by laser irradiation. Injection of turpentine, a chemical irritant, into the hind-paw skin (0.1 ml, SC) elicited neuronal discharges in the ipsilateral dorsal root, and these discharges were significantly inhibited or abolished by laser irradiation. These data suggest that laser irradiation may selectively inhibit nociceptive neuronal activities.
Autoimmunity Multiple sclerosis Experimental autoimmune encephalomyelitisMuili2012PLoS OneAmelioration of experimental autoimmune encephalomyelitis in C57BL/6 mice by photobiomodulation induced by 670 nm light.MouseDisease was induced with myelin oligodendrocyte glycoprotein (MOG) according to standard laboratory protocol. Mice received 670 nm light or no light treatment (sham) administered as suppression and treatment protocols. 670 nm light reduced disease severity with both protocols compared to sham treated mice. Disease amelioration was associated with down-regulation of proinflammatory cytokines (interferon-γ, tumor necrosis factor-α) and up-regulation of anti-inflammatory cytokines (IL-4, IL-10) in vitro and in vivo.
Oral Tooth replantation Carvalho2016Dent TraumatolEffects of diode laser irradiation and fibroblast growth factor on periodontal healing of replanted teeth after extended extra-oral dry time.RatDL, with or without FGF, reduced the occurrence of external root resorption and ankylosis. Periodontal healing was favored and some fiber reinsertion occurred only when FGF was used.
Wound healing Wounds Biphasic dose responsePinheiro2005Photomed Laser SurgPolarized light (400-2000 nm) and non-ablative laser (685 nm): a description of the wound healing process using immunohistochemical analysis.RatDose was also shown to have influence on the outcome of the treatment as on both cases, the use of 20 J/cm2 resulted on better effects on the healing process resulting on better organization and distribution of collagen fibers and influencing the numbers of myofibroblast The present study indicates that the use of 685-nm laser light or polarized light with a dose of 20 J/cm2 resulted in increased collagen deposition and better organization on healing wounds, and that the number of myofibroblasts is increased when polarized light is used.
Urinary bladder Ito2011Low Urin Tract SymptomsPulse Diode Laser Irradiation (830 nm) of Lumbosacral Spinal Roots Diminished Hyperreflexia-Induced by Acetic Acid or Prostaglandin E2 Infusion in Rat Urinary Bladder.RatDuring continuous saline infusion to the urinary bladder, neither continuous (1 W) nor pulse (10 W) laser irradiation altered the intercontraction interval and nerve firing during distention of the bladder. Pulse laser, but not continuous laser irradiation, increased the intercontraction interval with AA or PGE2 infusion and diminished nerve firing during distention of the bladder with AA or PGE2 infusion.
Brain Brain injury Chronic TBI patientsNaeser2014J NeurotraumaSignificant improvements in cognitive performance post-transcranial, red/near-infrared light-emitting diode treatments in chronic, mild traumatic brain injury: open-protocol study.Human Open-protocol studyEach LED cluster head had a 5.35 cm diameter (9 red diodes, 633 nm, and 52 NIR diodes, 870 nm were embedded into each LED cluster head); 22.48 cm2 in size; 500 mW total power; 22.2 mW/cm2 power density; continuous wave. A significant linear trend was observed for the effect of LED treatment over time for the Stroop test for Executive Function, Trial 3 inhibition (p=0.004); Stroop, Trial 4 inhibition switching (p=0.003); California Verbal Learning Test (CVLT)-II, Total Trials 1-5 (p=0.003); and CVLT-II, Long Delay Free Recall (p=0.006). Participants reported improved sleep, and fewer post-traumatic stress disorder (PTSD) symptoms, if present. Participants and family reported better ability to perform social, interpersonal, and occupational functions.
Oral Dry mouth (xerostomia) Lončar2011Photomed Laser SurgThe effect of low-level laser therapy on salivary glands in patients with xerostomia.Human (controlled)Effects of low-level laser therapy on salivary glands are not only stimulating, but also regenerative to a degree since the glandular response to the same amount of applied laser energy increased linearly over time.
Nerves PNS LLLT clusterShen2011InjuryLarge-area irradiated low-level laser effect in a biodegradable nerve guide conduit on neural regeneration of peripheral nerve injury in rats.RatEight weeks after implantation, walking track analysis showed a significantly higher sciatic function index (SFI) score (P<0.05) and better toe spreading development in the laser-treated group than in the sham-irradiated control group. For electrophysiological measurement, both the mean peak amplitude and nerve conduction velocity of compound muscle action potentials (CMAPs) were higher in the laser-treated group than in the sham-irradiated group. The two groups were found to be significantly different during the experimental period (P<0.005). Histomorphometric assessments revealed that the qualitative observation and quantitative analysis of the regenerated nerve tissue in the laser-treated group were superior to those of the sham-irradiated group. Thus, the motor functional, electrophysiologic and histomorphometric assessments demonstrate that LLL therapy can accelerate neural repair of the corresponding transected peripheral nerve after bridging the GGT nerve guide conduit in rats.
Oral Tooth extraction Immediate LLLT vs delayed LLLT (1 day after operation)Abdel-Alim2015Photomed Laser SurgA Comparative Study of the Effectiveness of Immediate Versus Delayed Photobiomodulation Therapy in Reducing the Severity of Postoperative Inflammatory Complications.HumanEighty patients with horizontally impacted mandibular third molars with no inferior alveolar canal approximation were recruited for this study. They were divided into two groups. The immediate group received PBM therapy immediately after surgery and on the 3rd day postoperatively. Subjects in the delayed group received PBM therapy on the 2nd and 4th days postoperatively. All subjects received 2 min of treatment using a 4 W laser beam, during which 171 J were delivered via a 2.8 cm(2) spot size. Clinical and statistical results showed a significant reduction in pain, trismus, and swelling in the immediate PBM therapy group compared with the delayed PBM therapy group.
Carpal tunnel Carpal tunnel syndrome Naeser2002Arch Phys Med RehabilCarpal tunnel syndrome pain treated with low-level laser and microamperes transcutaneous electric nerve stimulation: A controlled study.Human RCT/DB CrossoverEleven mild to moderate CTS cases who failed standard medical or surgical treatment for 3 to 30 months. Significant decreases in MPQ score, median nerve sensory latency, and Phalen and Tinel signs after the real treatment series but not after the sham treatment series. Patients could perform their previous work (computer typist, handyman) and were stable for 1 to 3 years. Comment: In addition LLLT, TENS treatment was also used. Comment: Parameters were insufficiently reported.
Oral Oral mucositis Wong & Wilder-Smith2002Cancer JPilot study of laser effects on oral mucositis in patients receiving chemotherapy.Human Pilot studyEleven of 15 patients experienced grade 0 mucositis, three patients experienced grade 1 to 2 mucositis, and one patient experienced grade 3 to 4 mucositis. In this pilot study, laser therapy significantly reduced the incidence and the severity of mucositis in chemotherapy patients. The laser therapy does not appear to promote wound healing by affecting the intraoral perfusion, as assessed by Doppler measurements.
Nerves Spinal cord Rochkind2002Neurol ResTransplantation of embryonal spinal cord nerve cells cultured on biodegradable microcarriers followed by low power laser irradiation for the treatment of traumatic paraplegia in rats.RatEleven of the 15 (73%) showed different degrees of active leg movements and gait performance, compared to 4 (44%) of the 9 rats with implantation alone. In a control group of seven rats with spinal cord transection and no transplantation or laser, six (86%) remained completely paralyzed. Three months after transection, implantation and laser irradiation, SSEPs were elicited in 69% of rats (p = 0.0237) compared to 37.5% in the nonirradiated group. The control group had no SSEPs response. Intensive axonal sprouting occurred in the group with implantation and laser. In the control group, the transected area contained proliferating fibroblasts and blood capillaries only. Comment: Parameters were insufficiently reported.
Brain Stroke Dose response Pulsed vs continous waveLapchak & De Taboada2010Brain ResTranscranial near infrared laser treatment (NILT) increases cortical adenosine-5-triphosphate (ATP) content following embolic strokes in rabbits.RabbitEmbolization decreased cortical ATP content in ischemic cortex by 45% compared to naive rabbits, a decrease that was attenuated by CW NILT which resulted in a 41% increase in cortical ATP content compared to the sham embolized group (p>0.05). The absolute increase in ATP content was 22.5% compared to naive rabbits. Following PW NILT, which delivered 5 (PW1) and 35 (PW2) times more energy than CW, we measured a 157% (PW1 p=0.0032) and 221% (PW2 p=0.0001) increase in cortical ATP content, respectively, compared to the sham embolized group. That represented a 41% and 77% increase in ATP content compared to naive control . This is the first demonstration that embolization can decrease ATP content in rabbit cortex and that NILT significantly increases cortical ATP content in embolized rabbits, an effect that is correlated with cortical fluence and the mode of NILT delivery.
Circulation Arterial restenosis Kipshidze1998J Am Coll CardiolPhotoremodeling of arterial wall reduces restenosis after balloon angioplasty in an atherosclerotic rabbit model.RabbitEndoluminal [low power red laser light] therapy was performed using a laser-balloon catheter with a 200 μm fiberoptic with a diffuse tip at the end to provide a uniform distribution of light in the radial and axial directions of the balloon (Fig. 1). Morphometric analysis demonstrated that intimal area was five times greater in the areas subjected to balloon treatment alone (25.3 ± 1.9 mm2) than in the balloon plus laser treatment sites (4.2 ± 0.7 mm2) Our experimental data indicate that endoluminal irradiation with [low power red laser light] prevents restenosis after balloon angioplasty in an atherosclerotic rabbit model. Endoluminal [low power red laser light] therapy may have a significant role in interventional cardiology, not only to prevent restenosis after coronary interventions but also to stabilize vascular endothelium so that progression or redevelopment of the disease is inhibited. Randomized studies are required to establish this as an effective clinical tool in humans. Comment: This paper was published in a very-high impact journal (IF = 17.8). The paper is also Open Access.
Brain Cognitive performance Rojas2012J Alzheimers DisLow-level light therapy improves cortical metabolic capacity and memory retention.RatExperiment 1 verified that LLLT increased the rate of oxygen consumption in the prefrontal cortex in vivo. Experiment 2 showed that LLLT-treated rats had an enhanced extinction memory as compared to controls. Experiment 3 showed that LLLT reduced fear renewal and prevented the reemergence of extinguished conditioned fear responses. Experiment 4 showed that LLLT induced hormetic dose-response effects on the metabolic capacity of the prefrontal cortex.
Eyes Age-related macular degenerationBegum2013PLoS OneTreatment with 670 nm light up regulates cytochrome C oxidase expression and reduces inflammation in an age-related macular degeneration model.MouseExposed animals had significant increase in cytochrome c oxidase (COX), which is a mitochondrial enzyme regulating oxidative phosphorylation. There was a significant reduction in complement component C3, an inflammatory marker in the outer retina. Vimetin and glial fibrillary acidic protein (GFAP) expression, which reflect retinal stress in Muller glia, were also significantly down regulated. There were also significant changes in outer retinal macrophage morphology.
Brain Cognitive performance Michalikova2008Neurobiol Learn MemEmotional responses and memory performance of middle-aged CD1 mice in a 3D maze: effects of low infrared light.MouseExposure to IR appeared to have no significant effects upon exploratory activity or anxiety responses. However, it elicited significant effects on working memory, with the IR middle-aged mice being more considerate in their decision making, which results in an overall improved cognitive performance which is comparable to that of young CD-1 mice.
Cosmetic medicine Body contouring Lach E2008J Cosmet Laser TherReduction of subcutaneous fat and improvement in cellulite appearance by dual-wavelength, low-level laser energy combined with vacuum and massage.Human RCTFat thickness decreased for the leg treated with laser-massage by 1.19 cm(2) (mean) and increased by 3.82 cm(2) (mean) for the control leg over time. The difference was statistically significant (p<0.001). Among those who completed the study, 82.26% responded to treatment. Individuals reported looser-fitting clothing and satisfaction with the procedure and results. Adverse effects were limited to occasional increases in urinary frequency. Low-level, dual-beam laser energy with massage appears to be safe and more efficacious than massage alone for reducing subcutaneous fat in the thighs of normal women.
Joints Crystal arthropathy Crystal arthropathy Acute gouty arthritisSoriano2006Photomed Laser SurgPhotobiomodulation of pain and inflammation in microcrystalline arthropathies: experimental and clinical results.Rat Human RCTFibrinogen, prostaglandin E(2), and TNF(alpha) concentrations in the rats injected with crystals and treated with laser decreased significantly as compared with the groups injected with crystals without treatment. Both laser therapy and diclofenac achieved rapid pain relief in patients with acute gouty arthritis without significant differences in efficacy. Laser therapy was more effective than diclofenac in patients with chronic pyrophosphate arthropathy and in patients with chronic apatite deposition disease.
Vestibular system Zhang2015J Vis ExpNear infrared (NIr) light increases expression of a marker of mitochondrial function in the mouse vestibular sensory epithelium.MouseFigure 2 shows a significant increase in β-actin normalized SOD-1 expression of more than 2-fold in young NIr-treated animals compared to young sham-treated animals (p < 0.01) and young NIr-blocked animals (p < 0.01). Older NIr-treated animals also showed more than a 2-fold up-regulation of SOD-1 when compared with older NIr-blocked animals (p < 0.05). Since there are currently no available, affordable, non-invasive methods of therapy to improve vestibular hair cell function, the application of external NIr radiation provides a potential strategy to counteract the impact of aging on cellular metabolism inthe vestibular sensory epithelium. Star: The article contains a very high-quality video depicting many of the relevant phases of the study execution. Two photographs are also supplied. Comment: Parameters werent reported, though they can be found from other papers of the same research group.
Circulation Arterial restenosis Derkacz2010Am J CardiolUsefulness of intravascular low-power laser illumination in preventing restenosis after percutaneous coronary intervention.Human ControlledFollow-up coronary angiography was performed after 6 months. The difference in the restenosis rate was insignificant (15.0% vs 32.4%); however, significant differences were observed in the minimal lumen diameter (2.18 ± 0.70 vs 1.76 ± 0.74 mm; p < 0.05), late lumen loss (0.53 ± 0.68 vs 0.76 ± 0.76 mm; p < 0.01), and the late lumen loss index (0.28 ± 0.39 vs 0.46 ± 0.43; p < 0.005) in favor of the laser group. In conclusion, the new therapy seemed effective and safe. Marked differences between late loss, late loss index, and minimal lumen diameter were observed.
Mechanisms Original research Greco1989Biochem Biophys Res CommunIncrease in RNA and protein synthesis by mitochondria irradiated with helium-neon laser.In vitroFollowing mitochondrial irradiation, both the rate and amount of incorporation of alpha-[32P]UTP and L-[35S]methionine, used to monitor RNA and protein synthesis respectively, proved to increase. Electrophoretic analysis made of the synthesis products clearly shows that He-Ne laser irradiation stimulates the synthesis of all mitochondrial transcription and translation products.
Penetration Hudson2013Photomed Laser SurgPenetration of laser light at 808 and 980 nm in bovine tissue samples.For 808 nm, 1 mW/cm(2) was achieved at 3.4 cm, but for 980 nm, 1 mW/cm(2) was achieved at only 2.2 cm depth of tissue. It was determined that 808 nm of light penetrates as much as 54% deeper than 980 nm light in bovine tissue.
Eyes Device: Mediray 04Koev2010Acta Medica BulgaricaHe-Ne low level laser therapeutic applications for treatment of acute iridocyclitisHumanFor irradiated eyes by LLLT, we have found that the healing period is shortened signi¿ cantly by 40 % (p<0,001) Comment: The parameters were very poorly reported. Even treatment time is unknown.
Eyes Foreign body in the cornea (corneal trauma)Koev2011Proc SPIEHe-Ne low level laser therapeutic applications for treatment of corneal trauma [Proceedings article]HumanFor irradiated eyes by LLLT, we have found that the healing period is shortened significantly by 42 % (p<0,001). Our results revealed that LLLT application is appropriate and perspective for recovery therapy after corpus alienum corneae extraction.
Oral Oral mucositis Gingival fibroblasts + LPSBasso2015Photochem PhotobiolBiomodulation of Inflammatory Cytokines Related to Oral Mucositis by Low-Level Laser Therapy.In vitroFor LPS-treated groups, LLLT promoted significant decreases in the expression of TNF-α, IL-6, and IL-8 at 1.5 J cm(-2) and 3 J cm(-2).
Mechanisms Original research Wang2016Sci RepInterplay between up-regulation of cytochrome-c-oxidase and hemoglobin oxygenation induced by near-infrared laser.HumanFor the first time, we demonstrated that 1064 nm laser can induce significant increases of CCO and HbO concentrations in a dose-dependent manner over time, as compared with placebo treatment. In addition, Δ[CCO] and Δ[HbO] displayed a clear linear relationship as the dose of LLLT increased. These results demonstrate the tremendous potential of broadband NIRS as a non-invasive, in vivo means to study mechanisms of photobiomodulation and perform treatment evaluations of LLLT.
Kidney Fibrosis UUO --> renal interstitial fibrosisOliveira2012Photomed Laser SurgLow-level laser therapy decreases renal interstitial fibrosis.RatFor the first time, we showed that LLLT had a protective effect regarding renal interstitial fibrosis. It is conceivable that by attenuating inflammation, LLLT can prevent tubular activation and transdifferentiation, which are the two processes that mainly drive the renal fibrosis of the UUO model. Note: See comment&reply of this paper. They discuss the mechanism a little bit.
Oral Osteonecrosis Scoletta2010Photomed Laser SurgEffect of low-level laser irradiation on bisphosphonate-induced osteonecrosis of the jaws: preliminary results of a prospective study.HumanFour weeks after LLLT, a statistically significant difference was observed for reported pain (p = 0.0001), clinical size (p = 0.0034), edema (p = 0.0005), and presence of pus and fistulas (p = 0.0078 and p = 0.03, respectively). Of course, this needs to be addressed further in larger and randomly controlled studies in different clinical settings.
Oncology Tumor cells Murine melanoma (B16F10) cellsPeidaee2016Med Biol Eng ComputIn vitro evaluation of low-intensity light radiation on murine melanoma (B16F10) cells.In vitroFrom irradiation of selected visible and near-infrared wavelengths, no visible changes were detected in cellular viability of either normal or cancer cells.
Oral Orthodontics Cepera2012Am J Orthod Dentofacial OrthopEffect of a low-level laser on bone regeneration after rapid maxillary expansion.HumanFrom the evaluation of bone density, the results showed that the laser improved the opening of the midpalatal suture and accelerated the bone regeneration process.
Nerves Spinal cord Veronez2016Lasers Med SciEffects of different fluences of low-level laser therapy in an experimental model of spinal cord injury in rats.RatFunctional evaluation and tactile sensitivity were improved after LLLT, at the higher fluence. Additionally, LLLT, at 750 and 1000 J/cm2, reduces the lesion volume and modulates the inflammatory process with decrease of CD-68 protein expression. These results suggest that LLLT at higher doses was effective in promoting functional recovery and modulating inflammatory process in the spinal cord of rats after SCI.
Oral Teeth Dentin regeneration Mechanisms Stem cellsArany2014Sci Transl MedPhotoactivation of endogenous latent transforming growth factor-β1 directs dental stem cell differentiation for regeneration.MouseFurther, an in vivo pulp capping model in rat teeth demonstrated significant increase in dentin regeneration after LPL treatment. These findings indicate a pivotal role for TGF-β in mediating LPL-induced dental tissue regeneration. More broadly, this work outlines a mechanistic basis for harnessing resident stem cells with a light-activated endogenous cue for clinical regenerative applications.
Toxins Snake venom MyonecrosisDourado2003Lasers Surg MedEffects of the Ga-As laser irradiation on myonecrosis caused by Bothrops Moojeni snake venom.MouseGa-As irradiation significantly decreased the amount of myonecrosis in all the periods tested (P < 0.05).
Muscle Muscle injury CrotoxinSilva2012Lasers Med SciGaAs 904-nm laser irradiation improves myofiber mass recovery during regeneration of skeletal muscle previously damaged by crotoxin.MouseGaAs laser at a dose of 3 J, but not 1.5 J, significantly increased the CSA of regenerating myofibers and reduced the PIMA and the area density of intramuscular connective tissue of CTX-injured muscles. Our results suggest that GaAs laser treatment at a dose of 3 J improves skeletal muscle regeneration by accelerating the recovery of myofiber mass.
Oral Oral mucositis Bensadoun1999Support Care CancerLow-energy He/Ne laser in the prevention of radiation-induced mucositis. A multicenter phase III randomized study in patients with head and neck cancer.Human RCT/DBGrade 3 mucositis occured with a frequency of 35.2% without LEL and of 7.6% with LEL (P<0.01). The frequency of severe pain (grade 3) was 23.8% without LEL, falling to 1.9% with LEL (P<0.05). Pain relief was significantly reduced throughout the treatment period (weeks 2-7). LEL therapy is capable of reducing the severity and duration of oral mucositis associated with radiation therapy. In addition, there is a tremendous potential for using LEL in combined treatment protocols utilizing concomitant chemotherapy and radiotherapy.
Bone Bone repair Blaya2006J Contemp Dent PractHistologic study of the effect of laser therapy on bone repair.Greater degrees of new bone formation and vertical regeneration were found in the irradiated groups than in the control group.
Oral Wound healing: palatal wounds Dose responseda Silva Neves2016Lasers Med SciComparison of two power densities on the healing of palatal wounds after connective tissue graft removal: randomized clinical trial.Human RCTGroup 1 presented statistically significant smaller wounds at day 7 (p > 0.05). None of the patients presented scars at the operated area, and all of the patients reported mild discomfort, with low consumption of analgesic pills. We concluded that the protocol of 60 J/cm(2) provided faster wound healing 7 days after removing the connective tissue graft for root coverage.
Lymphedema Kozanoglu2009Clin RehabilEfficacy of pneumatic compression and low-level laser therapy in the treatment of postmastectomy lymphoedema: a randomized controlled trial.Human RCTGroup II had better long-term results than group I. Low-level laser might be a useful modality in the treatment of postmastectomy lymphoedema. Comment: Parameters were poorly reported.
Wound healing Wounds Mendez2004J Clin Laser Med SurgDose and wavelength of laser light have influence on the repair of cutaneous wounds.RatGroup IV (lambda 830 nm and lambda 685 nm, 20 J/cm(2)) presented better results at the end of the experimental period. It is concluded that low-level light therapy (LLLT) can have a positive biomodulatory effect on the repair of cutaneous wounds.
Nerves PNS Dose response Biphasic dose responseZiago2017 epubLasers Med SciAnalysis of the variation in low-level laser energy density on the crushed sciatic nerves of rats: a morphological, quantitative, and morphometric study.RatGroups L0, L4, L10, and L50 exhibited diminished values of all the quantitative and morphometric parameters in comparison to the control group. The morphological, quantitative, and morphometric data revealed improvement after injury in groups L4, L10, and L50 (irradiated groups) compared to the injured-only group (L0); the best results, in general, were observed for the L10 group after 15 days of nerve injury.
Eyes Rezaei Kanavi2016Exp Eye ResShort-term effects of extremely low-frequency pulsed electromagnetic field and pulsed low-level laser therapy on rabbit model of corneal alkali burn.Rabbithe defect area was significantly less in the ELF, LLLT, and ELF + LLLT groups than in the control group (P < 0.005), and was comparable with that of the [medical therapy] group. However, the histopathological results showed that LLLT was superior to magnetic therapy in terms of lower intensity of corneal inflammation, and LLLT had a lower rate of keratocyte loss than medical treatment. Short-term LLLT is a noninvasive and safe treatment method that effectively improves the healing of corneas with alkali burns. Comment: Parameters were insufficiently reported.
Muscle Muscle injury Exercise-induced muscle injury Dose responseLiu2009Photomed Laser SurgEffects of low-level laser irradiation on rat skeletal muscle injury after eccentric exercise.RatHe-Ne laser irradiation at 43 J/cm2 inhibited muscle inflammation, significantly enhanced muscle SOD activity and significantly reduced serum CK activity and muscle MDA level at both 24 and 48 h after exercise, whereas the irradiation at 12 or 28 J/cm2 slightly inhibited muscle inflammation and significantly reduced serum CK activity at 48 h after exercise only (P<0.05). The photobiomodulation was dose-dependent, and the 43 J/cm2 dose was the most efficient among the doses used.
Wound healing Wounds Dose responseChung2010Photomed Laser SurgLaser photobiomodulation of wound healing in diabetic and non-diabetic mice: effects in splinted and unsplinted wounds.MouseHealing of splinted wounds was delayed compared to unsplinted wounds, but laser irradiation (1.6 J/day, 7 days) stimulated healing by re-epithelization and granulation tissue formation. Comment: The higher dose was better.
Hearing Hearing loss Gentamicin-induced hearing lossRhee2013J Biomed OptEffect of low-level laser treatment on cochlea hair-cell recovery after ototoxic hearing loss.RatHearing was significantly improved by laser irradiation. After LLLT treatment, both the hearing threshold and hair-cell count significantly improved. Star: Parameters were well reported, and some photographic material was supplied.
Oral Oral mucositis Cowen1997Int J Radiat Oncol Biol PhysLow energy Helium-Neon laser in the prevention of oral mucositis in patients undergoing bone marrow transplant: results of a double blind randomized trial.Human RCT/DBHelium-Neon laser treatment was well tolerated, feasible in all cases, and reduced high dose chemoradiotherapy-induced oral mucositis. Optimal laser treatment schedules still needs to be defined.
Oral Oral mucositis Barasch1995CancerHelium-neon laser effects on conditioning-induced oral mucositis in bone marrow transplantation patients.HumanHelium-neon laser treatment was well-tolerated and reduced the severity of conditioning-induced oral mucositis in BMT patients.
Nerves PNS Rochkind1986Acta Neurochir (Wien)Electrophysiological effect of HeNe laser on normal and injured sciatic nerve in the rat.RatHeNe irradiation was found to increase significantly the action potentials of the nerves. It was found to be a long-lasting effect, keeping an increase in the nerves action potential for more than eight months after irradiation has been stopped. A possible explanation for the way the irradiation acts on the nerve is suggested.
Nerves Systemic effects Systemic effectRochkind1989Lasers Surg MedSystemic effects of low-power laser irradiation on the peripheral and central nervous system, cutaneous wounds, and burns.RatHeNe laser irradiation applied to a crushed injured sciatic nerve in the right leg in a bilaterally inflicted crush injury, significantly increased the compound action potential in the left nonirradiated leg as well. The bilateral retrograde degeneration of the motor neurons of the spinal cord expected after the bilateral crush injury of the peripheral nerves was greatly reduced in the laser treated group.
Heart MI Diabetic mice Dose response LED phototherapy LED arrayKeszler2014Front PhysiolFar red/near infrared light-induced protection against cardiac ischemia and reperfusion injury remains intact under diabetic conditions and is independent of nitric oxide synthase.MouseHere we tested the hypothesis that NIR elicits protection in a diabetic mouse model where other cardioprotective interventions such as pre- and postconditioning fail, and that the protection is independent of nitric oxide synthase (NOS). NIR reduced infarct size dose dependently. Importantly, NIR-induced protection was preserved in a diabetic mouse model (db/db) and during acute hyperglycemia, as well as in endothelial NOS(-/-) mice and in wild type mice treated with NOS inhibitor L-NAME. Irradiation at 660 nm yields the highest release of NO, while at longer wavelengths a dramatic decrease of NO release can be observed. NIR is cardioprotective in the presence of diabetes or hyperglycemia. In summary, NIR applied during reperfusion protects the myocardium against infarction in an NO-dependent, but NOS-independent mechanisms, whereby mitochondria may be a target of NO released by NIR, leading to reduced reactive oxygen species generation during reperfusion. This unique mechanism preserves protection even during diabetes where other protective strategies fail. Comment: Beam area was not reported. According to the paper, LED array was used, so its likely the area was large.
Immunity Macrophages Listeria infectionLu2016Int J Biochem Cell BiolPhoto-enhancement of macrophage phagocytic activity via Rac1-mediated signaling pathway: Implications for bacterial infection.Mouse + in vitroHere, we demonstrated for the first time that LPLI enhanced the phagocytic activity of macrophages by stimulating the activation of Rac1. The overexpression of constitutively activated Rac1 clearly enhanced LPLI-induced phagocytosis, whereas the overexpression of dominant negative Rac1 exerted the opposite effect. The phosphorylation of cofilin was involved in the effects of LPLI on phagocytosis, which was regulated by the membrane translocation and activation of Rac1. Furthermore, the photoactivation of Rac1 was dependent on the Src/PI3K/Vav1 pathway. The inhibition of the Src/PI3K pathway significantly suppressed LPLI-induced actin polymerization and phagocytosis enhancement. Additionally, LPLI-treated mice exhibited increased survival and a decreased organ bacterial load when challenged with Listeria monocytogenes, indicating that LPLI enhanced macrophage phagocytosis in vivo. These findings highlight the important roles of the Src/PI3K/Vav1/Rac1/cofilin pathway in regulating macrophage phagocytosis and provide a potential strategy for treating phagocytic deficiency via LPLI.
Insect health Fruit fly Begum2015Biol LettNear-infrared light increases ATP, extends lifespan and improves mobility in aged Drosophila melanogaster.Fruit flyHere, we expose fruitflies daily to 670 nm radiation, revealing elevated ATP and reduced inflammation with age. Critically, there was a significant increase in average lifespan: 100-175% more flies survived into old age following 670 nm exposure and these had significantly improved mobility.
Pain Shoulder HILT (high-intensity laser therapy) HIRO 3.0 devicePekyavas & Baltaci2016Lasers Med SciShort-term effects of high-intensity laser therapy, manual therapy, and Kinesio taping in patients with subacromial impingement syndrome.Human RCT (?) Comparison trialHILT and MT were found to be more effective in minimizing pain and disability and increasing ROM in patients with SAIS. Further studies with follow-up periods are required to determine the advantages of these treatments conclusively.
Pain Back pain Alayat2014Lasers Med SciLong-term effect of high-intensity laser therapy in the treatment of patients with chronic low back pain: a randomized blinded placebo-controlled trial.Human RCT/DB (?)HILT combined with exercise appears to be more effective in patients with CLBP than either HLLT alone or placebo laser with exercise.
Wound healing Wounds InfectionsSantos2011Photomed Laser SurgInfluence of the combination of infrared and red laser light on the healing of cutaneous wounds infected by Staphylococcus aureus.RatHistological analysis showed that control subjects had a lower amount of blood vessels when compared with irradiated subjects. Irradiated subjects had more advanced resolution of inflammation compared with controls. Irradiated subjects also showed a more intense expression of the collagen matrix. The collagen fibers were mostly mature and well organized in these subjects at the end of the experimental time especially when both wavelengths were used. Comment: It seems unclear whether the red laser was 660 or 680 nanometers.
Oral Tooth extraction Diabetic ratsPark & Kang2012Lasers Med SciEffect of 980-nm GaAlAs diode laser irradiation on healing of extraction sockets in streptozotocin-induced diabetic rats: a pilot study.RatHistological observations and gene expression analyses revealed that groups 2 (normal rats with LLLT) and 4 (diabetic rats with LLLT) showed faster initial healing and more new alveolar bone formation than group 1 (normal rats without LLLT) and group 3 (diabetic rats without LLLT), respectively.
Kidney Glomerulonephritis Glomerulonephritis (crescentic)Yamata2013Lasers Med SciLow-level laser therapy improves crescentic glomerulonephritis in rats.RatHistological observations indicated that LLLT suppressed crescent formation and infiltration of ED1+ macrophages and CD8+ lymphocytes into the glomeruli. LLLT attenuated the levels of IL-1β and TNF-α messenger RNA in the renal cortex. Externally directed LLLT suppresses the activity of rat anti-GBM crescentic glomerulonephritis in rats. LLLT has the potential to be used for direct treatment of glomerulonephritis. Star: Parameters were well reported.
Nerves PNS Shen2013J Biomed Mater Res AEffects of large-area irradiated laser phototherapy on peripheral nerve regeneration across a large gap in a biomaterial conduit.RatHistomorphometric assessments revealed that the EGT/laser group had undergone more rapid nerve regeneration than the EGT/sham group. The laser-treated group also presented greater neural tissue area as well as larger axon diameter and thicker myelin sheath than the tube group without the laser treatment, indicating improved nerve regeneration. Thus, these assessments demonstrate that LLL therapy can accelerate the repair of a transected peripheral nerve in rats after being bridged with EGT conduit.
Nerves PNS Shen2013J Biomed Mater Res ANeural regeneration in a novel nerve conduit across a large gap of the transected sciatic nerve in rats with low-level laser phototherapy.RatHistomorphometric assessments showed that the EGT/LS group had undergone more rapid nerve regeneration than the EGT group. Therefore, motor function, electrophysiological reaction, muscular reinnervation, and histomorphometric assessments demonstrate that LLL therapy can accelerate the repair of a 15-mm transected peripheral nerve in rats after being bridged with the EGT nerve conduit.
Nerves Oral Inferior alveolar nerveMiloro2002Oral Surg Oral Med Oral Pathol Oral Radiol EndodLow-level laser effect on neural regeneration in Gore-Tex tubes.RabbitHistomorphometric evaluation revealed increased axonal density in the laser treated group as compared with the control.
Wound healing Burns 2nd degree burnRenno2011J Cosmet Laser TherEffect of low-level laser therapy (660 nm) on the healing of second-degree skin burns in rats.RatHistopathological analysis revealed a significant decrease in the necrotic area in the laser-treated group compared to the controls at days 7 and 14 post-injury. COX-2 positive cells were found in a strong pattern in the group submitted to laser therapy after 7 days. Regarding VEGF immunomarker, a significant VEGF immunoexpression was detected in the laser-exposed group after 14 days when compared to the negative control group. Taken together, our results demonstrate that laser therapy is able to promote skin repair of burned rats as a result of decreasing necrotic area and an up-regulation of COX-2 and VEGF immunoexpression.
Muscle Muscle injury CryolesionRodrigues2013J Rehabil Res DevEffects of 660 nm low-level laser therapy on muscle healing process after cryolesion.RatHistopathological findings revealed a lower inflammatory process in the laser-treated groups after 7 d. After 14 d, irradiated animals at both fluences showed higher granulation tissue, new muscle fibers, and organized muscle structure. After 21 d, full tissue repair was observed in all groups. Moreover, irradiated animals at both fluences showed smaller necrosis area in the first experimental period evaluated.
Oral TMJ Machado2016Lasers Med SciEffects of oral motor exercises and laser therapy on chronic temporomandibular disorders: a randomized study with follow-up.Human RCT/SBHowever, LLLT alone was not sufficient for TMD rehabilitation Seems that LLLT alone didnt outdo placebo treatment. Comment: Parameters were limitedly reported.
Oral Oral mucositis Ciais1992Bull Cancer[Laser therapy in the prevention and treatment of mucositis caused by anticancer chemotherapy]. [Article in French]HumanIatrogenic mucositis was observed during 43% of 53 chemotherapy cycles in the case control population. Curative laser therapy reduced the time to repair lesions and the rate of therapeutic modifications. For patients who received soft-laser therapy as a preventive measure, the incidence of oral complications was reduced to 6% during 101 cycles of chemotherapy. All of these patients, even those who have encountered mucositis before receiving preventive laser therapy, terminated their cancer therapy as originally scheduled. Well designed and carefully controlled trials will be necessary to define the place of helium-neon laser therapy in the repair and prevention of oral complications due to cancer chemotherapy.
Infections Bacteria Lipovsky2008Lasers Surg MedA possible mechanism for visible light-induced wound healing.In vitroIllumination with white light, 120 J/cm(2), caused a reduction of 62%, 83%, and 56% in the colony count of E. coli 1313, S. aureus 195 and S. marcescens, respectively, though no reduction in the viability of P. aeruginosa 1316 was demonstrated. The phototoxic effect was found to involve induction of ROS production by the bacteria. It was also found that illumination of S. aureus 195 and E. coli 1313 in the presence of pyocyanin, known to be secreted by P. aeruginosa, had a stronger bactericidal effect compared to illumination alone.
Oral Oral mucositis Pediatric patientsCauwels & Martens2011Eur Arch Paediatr DentLow level laser therapy in oral mucositis: a pilot study.Human Pilot studyImmediately after beaming the OM, pain relief was noticed. Depending on the severity of OM, on average, 2.5 treatments per lesion in a period of 1 week were sufficient to heal a mucositis lesion.
Carpal tunnel Carpal tunnel syndrome Fusakul2014Lasers Med SciLow-level laser therapy with a wrist splint to treat carpal tunnel syndrome: a double-blinded randomized controlled trial.Human RCT/DBImprovements were significantly more pronounced in the LLLT-treated group than the placebo group especially for grip strength at 5- and 12-week follow-ups. At 12-week follow-up, distal motor latency of the median nerve was significantly improved in the LLLT group than the placebo group (p < 0.05). LLLT therapy, as an alternative for a conservative treatment, is effective for treating mild to moderate CTS patients. It can improve hand grip strength and electroneurophysiological parameter with a carry-over effect up to 3 months after treatment for grip strength of the affected hands. Comment: In this study, they used red light as the placebo treatment, but it wasnt described accurately.
Oral Aphthous stomatitis Lalabonova & Daskalov2014Biotechnol Biotechnol EquipClinical assessment of the therapeutic effect of low-level laser therapy on chronic recurrent aphthous stomatitis.Human controlledIn 5 days, 75.6% of [LLLT group] patients showed complete epithelization, while in [pharmacotherapy group] the process was completed in only 37.8% of patients.
Inflammation Carrageenan inflammation Three carrageenan inflammatory models: (1) air-pouch (2) paw edema (3) granulomaHonmura1992Lasers Surg MedTherapeutic effect of Ga-Al-As diode laser irradiation on experimentally induced inflammation in rats.RatIn all cases, irradiation for less than 10 min was sufficient to inhibit the inflammation by 20-30%. The inhibitory effect of laser irradiation was not comparable to that of indomethacin (4 mg/kg, i.o.) in the air-pouch model and the paw-edema model, whereas laser irradiation was more potent than that of daily administration of indomethacin (1 mg/kg, i.o.) in the granuloma model. In future studies of the mechanism of laser effect, it should be noted that irradiating a rat twice, before and after the provocation of inflammation, was essential in order to achieve an effective inhibition of paw-edema.
Wound healing Ulcers Kubota J2004J Cosmet Laser TherDefocused diode laser therapy (830 nm) in the treatment of unresponsive skin ulcers: a preliminary trial.Human Controlled (n=5)In all five patients, the ulcers healed completely between 3 weeks and 7 months (22.8 +/- 19.3 weeks), without recurrence during a minimum 12-month follow-up. Defocused 830 nm diode laser therapy was well tolerated, and was very effective in the treatment of this small number of compromised skin ulcers of different aetiologies and in a large range of patient ages. Further controlled studies in larger populations are required. Defocused diode laser therapy nonetheless appears to be a very useful adjunctive method in the treatment of slow-to-heal and non-healing skin ulcers. Comment: The LLLT photo is black-and-white.
Brain Stroke Atherothrombotic stroke Transcranial LLLTDeTaboada2006Lasers Surg MedTranscranial application of low-energy laser irradiation improves neurological deficits in rats following acute stroke.RatIn all three laser-treated groups, a marked and significant improvement in neurological deficits was evident at 14, 21, and 28 days post stroke relative to the non-treated group. These observations suggest that LLLT applied at different locations in the skull and in a rather delayed-phase post stroke effectively improves neurological function after acute stroke in rats.
Muscle Exercise LED phototherapy LED cluster (33 or 9)Rossato2016Lasers Med SciEffect of pre-exercise phototherapy applied with different cluster probe sizes on elbow flexor muscle fatigue.Human RCT/DB CrossoverIn both large and small cluster probes (according parameters tested in this study) led to reduced fatigue in elbow flexor muscles, without difference between them.
Cells Energy metabolism HeLa cellsKaru1993Biull Eksp Biol Med.[Changes in the amount of ATP in HeLa cells under the action of He-Ne laser radiation]. [Article in Russian]In vitroIn cells of the exponential phase of growth, the amount of ATP (basal level 8 x 10(-16) mole/cell) starts to increase in 15 min after the irradiation with a maximum (170% above the basal level) at 20 min, and then decreases gradually to the basal level.
Radiation Gamma radiation Blue lightAbdul-Aziz & Tuorkey2010J Photochem Photobiol BArgon laser phototherapy could eliminate the damage effects induced by the ionizing radiation gamma radiation in irradiated rabbits.RabbitIn conclusion, argon laser therapy appears propitious protective effect against the hazard effects of gamma radiation.
Toxins Snake venom LED phototherapy LLLT vs LEDNadur-Andrade2012Lasers Med SciEffects of photobiostimulation on edema and hemorrhage induced by Bothrops moojeni venom.MouseIn conclusion, both LLL and LED irradiation reduced venom-induced local effects even though symptoms were already present.
Nerves Spinal cord Wu2012Lasers Med SciComparison of the effects of pulsed and continuous wave light on axonal regeneration in a rat model of spinal cord injury.RatIn conclusion, CW and pulsed laser light support axonal regeneration and functional recovery after SCI. Pulsed laser light has the potential to support axonal regrowth to spinal cord segments located farther from the lesion site. Therefore, the use of pulsed light is a promising noninvasive therapy for SCI.
Bone Bone metabolism Diabetic rats Exercise+LLLT on bone tissuePatrocínio-Silva2016Arch Endocrinol MetabLow-level laser therapy associated to a resistance training protocol on bone tissue in diabetic rats.RatIn conclusion, it can be suggested that the resistance exercise program stimulated bone metabolism, culminating in increased cortical tibial area, bone mineral content, bone mineral density and biomechanical properties. Furthermore, the association of physical exercises and LLLT produced higher values for bone mineral content and stiffness. Star: Parameters were well reported.
Oral Oral mucositis Khouri2009Braz Dent JUse of therapeutic laser for prevention and treatment of oral mucositis.HumanIn conclusion, laser reduced the frequency and severity of OM, suggesting that therapeutic laser can be used both as a new form of prevention and treatment of OM.
Diabetes mellitus Intravenous laser therapyKazemikhoo2016Lasers Med SciModifying effect of intravenous laser therapy on the protein expression of arginase and epidermal growth factor receptor in type 2 diabetic patients.HumanIn conclusion, laser therapy may have a beneficial effect for diabetic patients via decreasing arginase expression and activation of the NOS/NO pathway which increases NO production and vasodilation, and decreasing EGFR expression which may reduce neuroinflammation and its secondary damages.
Oncology Tumor growth Rhee2016Photomed Laser SurgLow-Level Laser Therapy Promoted Aggressive Proliferation and Angiogenesis Through Decreasing of Transforming Growth Factor-β1 and Increasing of Akt/Hypoxia Inducible Factor-1α in Anaplastic Thyroid Cancer.MouseIn conclusion, LLLT led to a decrease in TGF-β1 and increase of p-Akt/HIF-1α which resulted to overproliferation and angiogenesis of anaplastic thyroid carcinoma (ATC). Therefore, we suggest that LLLT can influence cancer aggressiveness associated with TGF-β1 and Akt/HIF-1α cascades in some poorly differentiated head and neck cancers. Star: Parameters were listed in a table, and a photograph was supplied.
Muscle Exercise Zagatto2016Lasers Med SciEffects of low-level laser therapy on performance, inflammatory markers, and muscle damage in young water polo athletes: a double-blind, randomized, placebo-controlled study.Human RCT/DBIn conclusion, LLLT resulted in a non-significant, but small to moderate effect on inflammatory and muscle damage markers and a moderate effect on performance in water polo players. In addition, the lack of positive results could be due to the small area covered by irradiation and this should be considered in future studies.
Toxins Snake venom EdemaBarbosa2008ToxiconEffect of low-level laser therapy in the inflammatory response induced by Bothrops jararacussu snake venom.MouseIn conclusion, LLLT significantly reduced the edema and leukocyte influx into the envenomed muscle, suggesting that LLLT should be considered as a potentially therapeutic approach for the treatment of the local effects of Bothrops species.
Muscle Exercise LLLT cluster (5)Baroni2010Eur J Appl PhysiolLow level laser therapy before eccentric exercise reduces muscle damage markers in humans.HumanIn conclusion, LLLT treatment before eccentric exercise was effective in terms of attenuating the increase of muscle proteins in the blood serum and the decrease in muscle force.
Muscle Muscle injury Acute injuryFernandes2013Lasers Med SciEffect of photobiomodulation on expression of IL-1β in skeletal muscle following acute injury.RatIn conclusion, LLLT was able to decrease IL-1β expression during the skeletal muscle repair following an acute injury.
Stem cells & regeneration Osteogenesis Yang2016Sci RepEffects of light-emitting diode irradiation on the osteogenesis of human umbilical cord mesenchymal stem cells in vitro.In vitroIn conclusion, low levels of LED light at a wavelength of 620 nm enhance the proliferation and osteogenic differentiation of hUMSCs during a long culture period.
Tendons Tenocyte migrationTsai2012PLoS OneLow-level laser irradiation stimulates tenocyte migration with up-regulation of dynamin II expression.In vitroIn conclusion, low-level laser irradiation stimulates tenocyte migration in a process that is mediated by up-regulation of dynamin 2, which can be suppressed by dynasore.
Bone Bone grafts de Oliveira Gonçalves2016J Photochem Photobiol BEffects of low-level laser therapy on autogenous bone graft stabilized with a new heterologous fibrin sealant.RatIn conclusion, low-level laser therapy stimulated bone regeneration and accelerated the process of integration of autogenous bone grafts.
Stem cells & regeneration Osteogenesis Peng2012Lasers Med SciThe effect of noncoherent red light irradiation on proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells.In vitroIn conclusion, nonconherent red light can promote proliferation but cannot induce osteogenic differentiation of MSCs in normal media, while it enhances osteogenic differentiation and decreases proliferation of MSCs in media with osteogenic supplements.
Pain Postoperative Dose response Biphasic dose response LED phototherapyCidral-Filho2014Lasers Med SciLight-emitting diode therapy induces analgesia in a mouse model of postoperative pain through activation of peripheral opioid receptors and the L-arginine/nitric oxide pathway.MouseIn conclusion, our results demonstrate, for the first time, that LEDT (950 nm, 80 mW/cm2) induced a dose–response analgesic effect in the model of PI in mice. At the energy density of 9 J/cm2, LEDT presented the most significant results through (1) activation of peripheral opioid receptors which involve, at least in part, the recruitment of opioid-containing leukocytes to the PI site and (2) activation of the l-arginine/NO pathway.
Tendons Achilles tendon Partial transection of tendonGuerra Fda2014Lasers Med SciPulsed LLLT improves tendon healing in rats: a biochemical, organizational, and functional evaluation.RatIn conclusion, pulsed LLLT leads to increased organization of collagen bundles and improved gait recovery.
Muscle Exercise Super Lizer™Demura2011J Physiol AnthropolEffect of linear polarized near-infrared light irradiation and light exercise on muscle performance.HumanIn conclusion, skin and muscle temperatures increased significantly with the active and passive warm-ups selected in this study. However, muscle strength, muscle power, and controlled force-exertion performance did not improve with either warm-up.
Muscle Exercise Felismino2014Lasers Med SciEffect of low-level laser therapy (808 nm) on markers of muscle damage: a randomized double-blind placebo-controlled trial.Human RCT/DBIn conclusion, the LLLT attenuated CK activity 72 h after the muscle damage protocol but did not have a positive effect on the recovery of strength performance.
Liver Liver regeneration Hepatectomy -> Liver regeneration LED phototherapy vs laserCastro-e-Silva2007Braz J Med Biol ResThe use of light-emitting diodes to stimulate mitochondrial function and liver regeneration of partially hepatectomized ratsRatIn conclusion, the present results suggest that LED irradiation promotes biological stimulatory effects during the early stage of liver regeneration and that LED is as effective as laser light, independent of the coherence, divergence and cromaticity.
Stem cells & regeneration Tenogenic induction Gomiero2016Vet Res CommunTenogenic induction of equine mesenchymal stem cells by means of growth factors and low-level laser technology.In vitroIn conclusion, the present study might furnish significant suggestions for developing an efficient approach for tenocyte induction since the external administration of bFGF2 and TGFβ3, along with LLLT, influences the differentiation of PB-MSCs towards the tenogenic fate.
Oral Root resorption Higashi2016Lasers Med SciThree consecutive days of application of LED therapy is necessary to inhibit experimentally induced root resorption in rats: a microtomographic study.RatIn conclusion, three daily LED therapy doses are required to inhibit root resorption after appliance of orthodontic forces.
Mechanisms Original research Amat2005J Photochem Photobiol BModification of the intrinsic fluorescence and the biochemical behavior of ATP after irradiation with visible and near-infrared laser light.In vitro ATP irradiationIn conclusion, visible and near-infrared light modifies the biochemical behavior of ATP in the hexokinase reaction and the fluorescence intensity of the molecule thus altering the Mg2+ binding strength to the oxygen atoms in the phosphate group. Note: Heger et al published a paper which claimed to disprove these findings. However, they used different parameters (9-fold lower irradiance), which could explain the different results.
Larynx Reflux laryngitis Experimental reflux laryngitis Combined wavelengthsMarinho2014Lasers Med SciPotential anti-inflammatory effect of low-level laser therapy on the experimental reflux laryngitis: a preliminary study.RatIn conclusion, we demonstrated that 105-J/cm2 infrared laser irradiation is potentially useful to control reflux laryngitis secondary to nasogastric intubation by reducing the influx of neutrophils to the injured area and improving the reparative collagenization of the laryngeal tissues. Therefore, we suggest that low-level laser is a promising therapy to be used in treatment of reflux-induced laryngitis.
Larynx Reflux laryngitis Experimental reflux laryngitis Combined wavelengthsMarinho2013J Photochem Photobiol BPotentiated anti-inflammatory effect of combined 780 nm and 660 nm low level laser therapy on the experimental laryngitis.RatIn conclusion, we demonstrated that the combined 17.5 J/cm2 at 780 nm and 10.0 J/cm2 at 660 nm successfully modulated early inflammatory response in experimental model of nasogastric intubation-induced reflux laryngitis. The possible mechanism involves the reduction in neutrophil infiltration, modulation of mast cells degranulation, and improved granulation tissue formation and collagen deposition in the injured area. [Star: Parameters were very well reported - and the combined wavelength experiment was interesting.]
Circulation Red blood cells Luo2015Lasers Med SciThe effects of low-intensity He-Ne laser irradiation on erythrocyte metabolism.In vitroIn hypertonic RBCs, LHNL irradiation may decrease the activity of energy-consuming enzymes, but increases the activity of energy-generating enzymes in glycolysis, to improve the RBC deformability.
Brain Alzheimers Disease Sommer AP2012Photomed Laser Surg670 nm laser light and EGCG complementarily reduce amyloid-β aggregates in human neuroblastoma cells: basis for treatment of Alzheimers disease?In vitroIn irradiated cells, Aβ(42) aggregate amounts were significantly lower than in nonirradiated cells.
Dermatology Radiation dermatitis DeLand2007Lasers Surg MedTreatment of radiation-induced dermatitis with light-emitting diode (LED) photomodulation.HumanIn LED-treated patients, 18 (94.7%) had grade 0 or 1 reaction and 1 (5.3%) had grade 2 reaction. Among controls, 4 (14.3%) had a grade 1 reaction, 24 (85.7%) had a grade 2 or 3 reaction. One LED-treated patient (5.3%) and 19 controls (67.9%) had to interrupt treatment. Note: Results are very interesting, but parameters are poorly reported.
Hearing Menieres disease Teggi2008Photomed Laser SurgEfficacy of low-level laser therapy in Ménières disease: a pilot study of 10 patients.Human Pilot studyIn our experience, LLLT seems to prevent vertigo spells in MD, although results indicate that it has a slower action than betahistine. Dose-dependent therapeutic effects could explain the last result. In our opinion, increased blood flow in the inner ear is the main mechanism leading to the therapeutic results.
Oral Endodontics Payer2005Oral Surg Oral Med Oral Pathol Oral Radiol EndodThe clinical effect of LLLT in endodontic surgery: a prospective study on 72 cases.Human ObservationalIn routine endodontic surgery cases, LLLT does not achieve a significant clinical benefit. Further, the results indicate a prominent placebo effect of the soft laser therapy. Comment: Placebo irradiation appeared to be better than control. Comment: One reason for the lack of result is the fact that the pain levels were already very low, so there was really nothing to improve. Comment: Two photographs were supplied.
Oral TMJ Salmos-Brito2013Lasers Med SciEvaluation of low-level laser therapy in patients with acute and chronic temporomandibular disorders.HumanIn summary, considering the non-invasive and harmless characteristics of this modality, and the significant improvement obtained in both groups (acute and chronic TMD) in subjective parameters (e.g., pain), as well as, in objective functional parameters (e.g., maximal mouth opening), LLLT may promote some anti-inflammatory effect and pain relief in painful and dysfunctional temporomandibular muscles.
Brain Parkinsons disease MPTP LED phototherapyPeoples2012Parkinsonism Relat DisordPhotobiomodulation enhances nigral dopaminergic cell survival in a chronic MPTP mouse model of Parkinsons disease.MouseIn summary, exposure to NIr either at the same time or well after chronic MPTP insult saved many SNc dopaminergic cells from degeneration.
Brain Parkinsons disease MPTPReinhart2016Exp Brain ResNear-infrared light (670 nm) reduces MPTP-induced parkinsonism within a broad therapeutic time window.MouseIn summary, irrespective of whether it was applied before, at the same time as or after MPTP insult, NIr reduced both behavioural and structural measures of damage by a similar magnitude. There was a broad therapeutic time window of NIr application in relation to the stage of toxic insult, and the NIr was fast-acting and long-lasting. Star: The paper included a photograph of LLLT application.
Muscle Exercise Malta Ede2016Lasers Med SciAcute LED irradiation does not change the anaerobic capacity and time to exhaustion during a high-intensity running effort: a double-blind, crossover, and placebo-controlled study : Effects of LED irradiation on anaerobic capacity and performance in running.Human RCT/DB CrossoverIn summary, LEDT after a high-intensity running effort did not alter the MAODALT, metabolic energy pathways, or high-intensity running performance.
Wound healing Burns Wavelength comparison Dose optimizationRathnakar2016Lasers Med SciPhoto-biomodulatory response of low-power laser irradiation on burn tissue repair in mice.MouseIn summary, low-power lasers at wavelength 632.8, 785, and 830 nm have shown beneficial effects in burn wound healing, compared to untreated controls. Further, 3-J/cm2 fluence of 830 nm exhibited the best response among the other wavelengths and fluences under study in enhancing wound repair in full thickness burn injury in mice. The treatment promoted proliferation, neovascularization, deposition of collagen, denser packing of connective tissue, and epithelialization at faster rate to contract the wound, compared to untreated controls. Surprisingly, the response observed in the single exposure of 3-J/cm2 treatment of 830 nm was equivalent to the reference standard applied on daily basis. Star: Nice work with a huge amount of mice (n=170).
Brain Parkinsons disease LED phototherapyShaw2010J Comp NeurolNeuroprotection of midbrain dopaminergic cells in MPTP-treated mice after near-infrared light treatment.MouseIn summary, our results indicate that NIr light treatment offers neuroprotection against MPTP toxicity for dopaminergic cells in the SNc, but not in the ZI-Hyp.
Brain Parkinsons disease MPTPShaw2012Parkinsons DisPatterns of Cell Activity in the Subthalamic Region Associated with the Neuroprotective Action of Near-Infrared Light Treatment in MPTP-Treated Mice.MouseIn summary, our results indicated that NIr had long lasting effects on the activity of cells located deep in the brain and had repaired partially the abnormal activity generated by the parkinsonian toxin.
Brain Parkinsons disease Moro2013BMC NeurosciPhotobiomodulation preserves behaviour and midbrain dopaminergic cells from MPTP toxicity: evidence from two mouse strains.MouseIn summary, our results revealed the neuroprotective benefits of NIr treatment after parkinsonian insult at both cellular and behavioural levels and suggest that Balb/c strain, due to greater penetration of NIr through skin and fur, provides a clearer model of protection than the C57BL/6 strain.
Dermatology Herpes zoster Fan & Wang2015Dermatol SurgA Novel Treatment of Herpes Zoster Pain With Pulsed Laser Irradiation.LetterIn summary, the authors found in the treatment of 5 herpes zoster patients that 1,064-nm Nd:YAG laser irradiation could significantly alleviate herpetic pain with persisting effect and no apparent adverse effect. Comment: The parameters were poorly reported.
Brain Parkinsons disease MPTP Systemic effectsJohnstone2014NeuroscienceIndirect application of near infrared light induces neuroprotection in a mouse model of parkinsonism – An abscopal neuroprotective effectMouseIn summary, the findings suggest that treatment of a remote tissue with NIr is sufficient to induce protection of the brain, reminiscent of the ‘abscopal effect’ sometimes observed in radiation treatment of metastatic cancer. This discovery has implications for the clinical translation of light-based therapies, providing an improved mode of delivery over transcranial irradiation.
Muscle Exercise LED phototherapy LED cluster (5)Fritsch2016Lasers Med SciEffects of low-level laser therapy applied before or after plyometric exercise on muscle damage markers: randomized, double-blind, placebo-controlled trial.Human RCT/DBIn summary, the LLLT protocol used in this study had no effect on strength fall induced by muscle damage; then, caution is needed for recommending phototherapy to reduce this functional impairment. However, LLLT applied both before and after plyometric exercise was able to reduce the muscular echo intensity, indicating a reduced inflammatory response mediated by phototherapy. In addition, our findings suggest a slight effect (not statistically significant) on muscle soreness, which might seem too small for most individuals but can make a crucial difference for high-performance athletes.
Skin Vitiligo Lan2009Br J DermatolLow-energy helium-neon laser induces melanocyte proliferation via interaction with type IV collagen: visible light as a therapeutic option for vitiligo.In vitroIn summary, we have demonstrated that the He-Ne laser imparts a growth stimulatory effect on functional melanocytes via mitochondria-related pathways and proposed that other minor pathways including DNA damage may also be inflicted by laser treatment on irradiated cells. More importantly, we have completed the repigmentation scheme of vitiligo brought about by He-Ne laser light in vitro and provided a solid theoretical basis regarding how the He-Ne laser induces recovery of vitiligo in vivo.
Brain Parkinsons disease MPTPEl Massri2016Int J NeurosciThe effect of different doses of near infrared light on dopaminergic cell survival and gliosis in MPTP-treated mice.MouseIn summary, we showed that neuroprotection by NIr irradiation in MPTP-treated mice was dose-dependent; with increasing MPTP toxicity, higher doses of NIr were required to protect cells and reduce astrogliosis.
Brain Parkinsons disease MPTP LED phototherapy Retinal damage (eyes)Peoples2012ISRN NeurolSurvival of Dopaminergic Amacrine Cells after Near-Infrared Light Treatment in MPTP-Treated Mice.MouseIn summary, we showed that NIr treatment was able to both protect (simultaneous series) and rescue (posttreatment series) TH(+) cells of the retina from parkinsonian insult.
Brain Parkinsons disease 6-OHDA Light delivery into the brain via optical fiberReinhart2016J NeurosurgIntracranial application of near-infrared light in a hemi-parkinsonian rat model: the impact on behavior and cell survival.MouseIn summary, when delivered at the appropriate power, delivery mode, and dosage, NIr treatment provided both improved behavior and neuroprotection in 6-OHDA-lesioned rats.
Penetration Teeth Turrioni2013Am J DentLED light attenuation through human dentin: a first step toward pulp photobiomodulation after cavity preparation.Human dentin samplesIn terms of minimum (0.2 mm) and maximum (1.0 mm) dentin thicknesses, the percentage of light attenuation varied from 49.3% to 69.9% for blue light, 42.9% to 58.5% for red light and 39.3% to 46.8% for infrared.
Radiation Cancer radiotherapy Prostate cancer patientsZharinov2010Laser TherLate radiation lesions of urinary bladder and rectum in patients with prostate cancer after external radiation therapy and phototherapy with low power near infrared laser.HumanIn the control group the radiation damage of urinary bladder and rectum appeared in 7.6% and 10.7% of patients, while in the main group - in 1.95% and 2.92%, respectively (p < 0.01). Thus, the course of phototherapy with the near infrared low power laser at performance of radiotherapy decreases incidence of radiation damages of urinary bladder and rectum in patients with prostate cancer.
Oral Dental implants LED phototherapyGokmenoglu2014Photomed Laser SurgThe effect of light-emitting diode photobiomodulation on implant stability and biochemical markers in peri-implant crevicular fluid.HumanIn the control group, significant reduction of ISQ values from week 2 to week 12 were demonstrated. In the LED group, baseline ISQ values were maintained during the study and no significant changes were observed. LED application to surgical area has a positive effect on the osseointegration process, and implant stability can be maintained.
Nerves PNS Santos2012Lasers Med SciFunctional and morphometric differences between the early and delayed use of phototherapy in crushed median nerves of rats.RatIn the early group, the first laser treatment started immediately after surgery, and in the delayed group, after 7 days. The untreated, early, and delayed groups presented a 50, 57, and 81% degree of functional recovery, respectively, at 21 days after injury, with a significant difference between the untreated and delayed groups. The results suggest that the nerves irradiated with low-power laser exhibit myelinated fibers of greater diameter and a better recovery of function.
Muscle Atrophy Muscle denervationRochkind & Shainberg2013Photomed Laser SurgProtective effect of laser phototherapy on acetylcholine receptors and creatine kinase activity in denervated muscle.RatIn the early stages of muscle atrophy, laser phototherapy may preserve the denervated muscle by maintaining CK activity and the amount of AChR.
Oral Periodontium Gündoğar2016Lasers Med SciThe effect of low-level laser therapy on non-surgical periodontal treatment: a randomized controlled, single-blind, split-mouth clinical trial.Human RCT/SB Split-mouthIn the first month, PPD levels were significantly (p < 0.05) lower in the SRP + LLLT group than in the SRP group. At the third and sixth months, CAL, PPD, and GI were significantly (p < 0.05) lower in the SRP + LLLT group than in the SRP group. Differences in GCF cytokines levels among the group were not statistically significant. Within the limitations of this study, it is indicated that LLLT as an adjunct to non-surgical periodontal treatment has a positive impact on clinical parameters.
Bone Bone repair Diabetic rats Tibial bone healingMagri2015Lasers Med SciPhotobiomodulation and bone healing in diabetic rats: evaluation of bone response using a tibial defect experimental model.RatIn the histological and morphometric evaluation, all laser-treated groups showed a better histological pattern and a higher amount of newly formed bone compared to DCG. An intense RUNX2 immunoexpression was observed in the laser-treated groups, 15 days after the surgery. There was no statistical difference in the biomechanical analysis among the groups. In conclusion, PBM, in all fluences used, showed an osteogenic potential in bone healing of diabetic rats
Brain Alzheimers Disease Transgenic mice: - K3 - APP/PS1Purushothuman2014Alzheimers Res TherPhotobiomodulation with near infrared light mitigates Alzheimers disease-related pathology in cerebral cortex - evidence from two transgenic mouse models.MouseIn the K3 mice, NIr treatment was associated with a reduction in hyperphosphorylated tau, neurofibrillary tangles and oxidative stress markers (4-hydroxynonenal and 8-hydroxy-2′-deoxyguanosine) to near wildtype levels in the neocortex and hippocampus, and with a restoration of expression of the mitochondrial marker cytochrome c oxidase in surviving neurons. In the APP/PS1 mice, NIr treatment was associated with a reduction in the size and number of amyloid-β plaques in the neocortex and hippocampus.
Oral Oral mucositis Pediatric patients undergoing chemo/HSCTKuhn2009J Pediatr Hematol OncolLow-level infrared laser therapy in chemotherapy-induced oral mucositis: a randomized placebo-controlled trial in children.Human RCTIn the laser group, the mean of OM duration was 5.8±2 days and in the placebo group was 8.9±2.4 days (P=0.004).
Pain Back pain Djavid2007Aust J PhysiotherIn chronic low back pain, low level laser therapy combined with exercise is more beneficial than exercise alone in the long term: a randomised trial.Human RCT/DB (?)in the laser therapy plus exercise group pain had reduced by 1.8 cm (95% CI 0.1 to 3.3, p = 0.03), lumbar range of movement increased by 0.9 cm (95% CI 0.2 to 1.8, p < 0.01) on the Schober Test and by 15 deg (95% CI 5 to 25, p < 0.01) of active flexion, and disability reduced by 9.4 points (95% CI 2.7 to 16.0, p = 0.03) more than in the exercise group at 12 weeks.
Tendons Tennis elbow Roberts2013Lasers Surg MedThe effectiveness of therapeutic class IV (10 W) laser treatment for epicondylitis.Human RCT/DBIn the laser treated group handgrip strength improved by 17 ± 3%, 52 ± 7%, and 66 ± 6% at 3, 6, and 12 months respectively; function improved by 44 ± 1%, 71 ± 3%, and 82 ± 2%, and pain with resistance to extension of the middle finger was reduced by 50 ± 6%, 93 ± 4%, and 100 ± 1% at 3, 6 and 12 months, respectively. In contrast, no changes were seen until 12 months following sham treatment (12 months: strength improved by 13 ± 2%, function improved by 52 ± 3%, pain with resistance to extension of the middle finger reduced by 76 ± 2%). [See additional info]
Circulation Endothelium Szymczyszyn2016Lasers Med SciEffect of the transdermal low-level laser therapy on endothelial function.HumanIn the LG, a significant increase in GSH levels and considerable decrease in angiostatin concentration following the LLLT were observed. No significant differences in levels of the VEGF, FGF, SDMA, ADMA were observed.LLLT modifies vascular endothelial function by increasing its antioxidant and angiogenic potential. We found no significant differences in levels of the nitric oxide pathway metabolites within 24 h following the LLLT irradiation.
Oral Oral mucositis HSCT patientsSilva2011Photomed Laser SurgThe prevention of induced oral mucositis with low-level laser therapy in bone marrow transplantation patients: a randomized clinical trial.Human RCTIn the LLLT group, 57.1% of patients had an OM grade 0, 9.6% had grade 1, and 33.3% had grade 2, whereas in the control group, only 4.8% of patients were free of OM (grade 0).
Wound healing Wounds Gonçalves2013Pathol Res PractComparative study of the effects of laser photobiomodulation and extract of Brassica oleracea on skin wounds in wistar rats: A histomorphometric study.RatIn the present study, LLLT and balsam and Ointment B. oleracea were more effective at reducing the size of the wounds compared to the control group. LLLT and B. oleracea application promoted acceleration of wound healing, enhanced remodeling and repair.
Oral Orthodontics Lee2016Angle OrthodCombined effect of photobiomodulation with a matrix metalloproteinase inhibitor on the rate of relapse in rats.RatIn the present study, the combined effect of LLLT with doxycycline on both relapse rate and MMP expression in the PDL was proved to be antagonistic, although the stimulatory effect of LLLT and inhibitory effect of doxycycline were separately verified.
Nerves PNS Mandelbaum-Livnat2016Photomed Laser SurgPhotobiomodulation Triple Treatment in Peripheral Nerve Injury: Nerve and Muscle Response.RatIn the present study, the effectiveness of triple treatment laser phototherapy, namely, applied simultaneously at three areas: injured area of the peripheral nerve, corresponding segments of the spinal cord, and corresponding denervated muscle (triple treatment), was evaluated for the treatment of incomplete PNI in rats with the ultimate goal of achieving improved limb function. The present study and our previous investigations showed that the laser phototherapy increases biochemical activity and improves morphological recovery in muscle and, thus, could have direct therapeutic applications on muscle, especially during progressive atrophy resulting from PNI.
Pancreas Regeneration Dose responseHuang2015J Cell BiochemPhotoactivation of Akt1/GSK3β Isoform-Specific Signaling Axis Promotes Pancreatic β-Cell Regeneration.In the present study, we showed that LPLI promoted β-cell replication and cell cycle progression through activation of Akt1/GSK3β isoform-specific signaling axis. Inhibition of PI3-K/Akt or GSK3 with specific inhibitors dramatically reduced or increased LPLI-induced β-cell replication, revealing Akt/GSK3 signaling axis was involved in β-cell replication and survival upon LPLI treatment.
Muscle Myopathy Experimental myopathyDávila2011Laser TherLow level laser therapy on experimental myopathy.In the present work, LLLT caused great changes in inflammatory biomarkers, with decreased levels of NO in rats with experimental myopathies and significant muscle recovery. Comment: Parameters were reported incompletely.
Oral Tooth extraction Wisdom tooth Postoperative analgesiaMarković & Todorović2006Oral Surg Oral Med Oral Pathol Oral Radiol EndodPostoperative analgesia after lower third molar surgery: contribution of the use of long-acting local anesthetics, low-power laser, and diclofenac.Human LLLT+dicloIn the second part of the study, low-power laser irradiation significantly reduced postoperative pain intensity in patients premedicated with diclofenac, compared with the controls.
Carpal tunnel Carpal tunnel syndrome Yagci2009Clin RheumatolComparison of splinting and splinting plus low-level laser therapy in idiopathic carpal tunnel syndrome.Human RCTIn the third-month control, SLLLT group had significant improvements on both clinical and [nerve conduction study] parameters (median motor nerve distal latency, median sensory nerve conduction velocities, BQ symptom severity scale, and BQ functional capacity scale) while S group had only symptomatic healing (BQ symptom severity scale). The grip strength of splinting group was decreased significantly. According to clinical response criteria, in SLLLT group, five (23.8%) patients had full and 12 (57.1%) had partial recovery; four (19%) patients had no change or worsened. In S group, one patient (4.2%) had full and 17 (70.8%) partial recovery; six (25%) patients had no change or worsened. Additionally, applied laser therapy provided better outcomes on [nerve conduction study] but not in clinical parameters in patients with CTS.
Oral Ulcers Cabras2016Case Rep DentLaser Photobiomodulation for a Complex Patient with Severe Hydroxyurea-Induced Oral Ulcerations.Human Case reportIn this case report laser photobiomodulation has achieved pain control and has contributed to the healing of oral ulcers without any adverse effect; this has permitted a reduction in the dose of systemic corticosteroids and the suspension of the use of the topic ones, due to the long-term stability of oral health, even after the interruption of LLLT sessions.
Muscle Exercise LLLT vs LED LED phototherapy LED clusterLeal Junior2009Photomed Laser SurgComparison between single-diode low-level laser therapy (LLLT) and LED multi-diode (cluster) therapy (LEDT) applications before high-intensity exercise.Human RCT/DB CrossoverIn this experimental set-up, only the active LEDT probe decreased post-exercise CK levels after the Wingate cycle test. Neither performance nor blood lactate levels were significantly affected by this protocol of pre-exercise LEDT or LLLT.
Diabetes mellitus Ulcers and wounds Wavelength comparison Green light therapyAl-Watban FA2009Photomed Laser SurgLaser therapy converts diabetic wound healing to normal healing.RatIn this induced-diabetes model, wound and burn healing were improved by 40.3% and 45%, respectively, in 633-nm laser dosimetry experiments, and diabetic wound and burn healing was accelerated by phototherapy. This indicates that the healing rate was normalized in the phototherapy-treated diabetic rats. Star: A remarkably huge study with 893 rats!
Brain Parkinsons disease Genetic modelOueslati2015PLoS OnePhotobiomodulation Suppresses Alpha-Synuclein-Induced Toxicity in an AAV-Based Rat Genetic Model of Parkinsons Disease.RatIn this model, daily exposure of both sides of the rats head to 808-nm near-infrared light for 28 consecutive days alleviated α-syn-induced motor impairment, as assessed using the cylinder test. This treatment also significantly reduced dopaminergic neuronal loss in the injected substantia nigra and preserved dopaminergic fibers in the ipsilateral striatum.
Oral Aphthous stomatitis Biolase Ezlase 940Misra2013BMJ Case Rep940 nm diode laser therapy in management of recurrent apthous ulcer.Human Case reportIn this paper one patient with RAS was treated using a 940 nm diode laser for symptomatic relief of pain and burning sensation and healing of ulcer.
Eyes Ivandic2009Photomed Laser SurgEarly diagnosis of ocular hypertension using a low-intensity laser irradiation test.In this study of a case series we examined the potential use of LILI as a tool to determine the individual physiological IOP. The aim was to differentiate between normoand hypertensive eyes by classifying changes in IOP after irradiation of the limbus area of the eye with a weak laser. We report here for the first time that LILI of the limbus area of the eye may lower the IOP. The laser power used here does not cause thermal damage and may well reach the ciliary body and the trabecular meshwork as previously shown. A study limitation is the lack of long-term observations after LILI. It is currently unknown, how long the effects of a single LILI treatment last. The largest decrease in IOP (26%) was observed in eyes with a pathological baseline IOP of >21 mm Hg which exhibited ocular hypertension without damage. However, LILI also decreased IOP in most eyes (73%) with a normotensive baseline IOP reaching a mean level of 14.1 mm Hg in this group, which is in agreement with the accepted population-based normative IOP. The diagnostic LILI test introduced here, may be particularly useful to detect latent ocular hypertension in eyes with apparently ‘‘normotensive’’ but potentially nonphysiological IOP, if ocular hypertension is associated with an open angle. Eyes with ocular hypertension may be at risk of developing glaucoma later on. Untreated ocular hypertension leads to glaucoma in 9.5% of cases.
Nerves Diabetic neuropathy Perić Z2007Srp Arh Celok Lek[Influence of low-intensity laser therapy on spatial perception threshold and electroneurographic finding in patients with diabetic polyneuropathy]. [Article in Serbian]HumanIn this study we registered significant decrease of SPT and increase of NMMCV after LILT and that indicated a favourable effect of this treatment in analysed patients with painful DPN. In our opinion these results need further investigation.
Tendons Digital flexor tendons MLS laser therapy Biphasic dose response (?)Iacopetti2015Photomed Laser SurgEffect of MLS(®) laser therapy with different dose regimes for the treatment of experimentally induced tendinopathy in sheep: pilot study.SheepIn this study, clinical and histological evaluation demonstrated that a therapeutic dose <5 J/cm(2) furnished an anti-inflammatory effect, and induced a decrease of fibroblasts and vessel area. Overall, our results suggest that MLS laser therapy was effective in improving collagen fiber organization in the deep digital flexor tendon. The aggravation of the inflammatory condition, observed during the applications of MLS laser therapy in the first group, seems to indicate that, for the treatment of an acute tendinitis with this type of laser emission, the dose of 5 J/cm2 was excessive for the therapeutic effect. Results from histological examinations indicate that both treatments induced a statistically significant cell number decrease, although only in the second group did the values return to normal. Moreover, the MLS dose of 2.5 J/ cm2 (group 2) caused a significant decrease of the vessel area
Fertility, genitals, etc. Sperm motility Sea urchin spermDrozdov2014Dokl Biochem BiophysInfluence of low-intensity red diode and laser radiation on the locomotor activity of sea urchin sperm.In vitroIn this study, we showed that lowintensity red light diode and laser radiation affect the locomotor activity of sea urchin sperms, 2–5 times increasing the per centage of active cells depending on the time elapsed after exposure.
Wound healing Pressure ulcer Lucas2003Lasers Med SciEfficacy of low-level laser therapy in the management of stage III decubitus ulcers: a prospective, observer-blinded multicentre randomised clinical trial.Human RCT/SB MulticenterIn this trial we found no evidence that justifies using low-level laser therapy as an adjuvant to the consensus decubitus ulcer treatment.
Carpal tunnel Carpal tunnel syndrome Evcik2007Photomed Laser SurgLaser therapy in the treatment of carpal tunnel syndrome: a randomized controlled trial.Human RCT/SBIn using LLLT, (1) there was no difference relative to pain relief and functional capacity during the follow-up in CTS patients; (2) there were positive effects on hand and pinch grip strengths.
Nerves PNS Nerve injuryAnders2014Lasers Surg MedIn vitro and in vivo optimization of infrared laser treatment for injured peripheral nerves.In vitro & RabbitIn vitro, 980 nm wavelength light at 10 mW/cm(2) significantly improved neurite elongation at energy densities between 2 and 200 mJ/cm(2) . In vivo penetration of the infrared light measured in anesthetized rabbits showed that on average, 2.45% of the light applied to the skin reached the depth of the peroneal nerve. The in vivo pilot study data revealed that the 4 W parameters inhibited nerve regeneration while the 2 W parameters significantly improved axonal regrowth. For the final set of experiments, the irradiated group performed significantly better in the toe spread reflex test compared to the control group from week 7 post-injury, and the average length of motor endplates returned to uninjured levels. Star: An exceptionally thorough study, with a huge amount of interesting data!
Heart MI MI Systemic effectTuby2011Lasers Surg MedInduction of autologous mesenchymal stem cells in the bone marrow by low-level laser therapy has profound beneficial effects on the infarcted rat heart.RatInfarct size and ventricular dilatation were significantly reduced (76% and 75%, respectively) in the laser-treated rats 20 minutes post-MI as compared to the control-non-treated rats at 3 weeks post-MI. There was also a significant 25-fold increase in cell density of c-kit+ cells in the infarcted area of the laser-treated rats (20 minutes post-MI) as compared to the non-laser-treated controls. [Star: interesting results!]
Toxins Snake venom Silva2016PLoS OnePhotobiomodulation Protects and Promotes Differentiation of C2C12 Myoblast Cells Exposed to Snake Venom.In vitroInfrared and red laser at all energy densities were able to considerably decrease venom-induced cytotoxicity. Laser irradiation induced myoblasts to differentiate into myotubes and this effect was accompanied by up regulation of MyoD and specially myogenin. Moreover, LLL was able to reduce the extracellular while increased the intracellular ATP content after venom exposure.
Infections Bacteria PulsingFonseca2012Lasers Med SciLow-level infrared laser effect on plasmid DNA.In vitroInfrared laser action can differently affect the survival of plasmids in E. coli cells proficient and deficient in DNA repair mechanisms, therefore, laser therapy protocol should take into account fluencies, frequencies and wavelength of laser, as well as tissue conditions and genetic characteristics of cells before beginning treatment.
Muscle Muscle injury Cryoinjuryde Souza2011Lasers Med SciPhototherapy with low-level laser affects the remodeling of types I and III collagen in skeletal muscle repair.RatInGaAlP diode laser within the power parameters and conditions tested had a biostimulatory effect at the regenerative and fibrotic phases of the skeletal muscle repairs, by promoting angiogenesis, reducing myonecrosis, and inducing types I and III collagen synthesis, following cryoinjury in rat.
Ligaments ACL injury Ligament transection Biphasic dose responseBublitz2014Lasers Med SciLow-level laser therapy prevents degenerative morphological changes in an experimental model of anterior cruciate ligament transection in rats.RatInitial signs of tissue degradation were observed in CG. Interestingly, laser-treated animals presented a better tissue organization, especially at the fluence of 10 J/cm(2). Furthermore, laser phototherapy was able of modulating some of the aspects related to the degenerative process, such as the prevention of proteoglycans loss and the increase in cartilage area. However, LLLT was not able of modulating chondrocytes proliferation and the immunoexpression of markers related to inflammatory process (IL-1 and MMP-13). This study showed that 808 nm laser, at both fluences, prevented features related to the articular degenerative process in the knees of rats after ACLT.
Pain Neuropathic Irradiation of affected hind paw + dorsal root ganglia + spinal cord regions Microglia (M2 activation by LLLT)Kobiela Ketz2016 epubPain MedCharacterization of Macrophage/Microglial Activation and Effect of Photobiomodulation in the Spared Nerve Injury Model of Neuropathic Pain.Injured groups demonstrated mechanical hypersensitivity 1-30 days post-operatively. Photobiomodulation-treated animals began to recover after two treatments; at day 26, mechanical sensitivity reached baseline. Peripheral nerve injury caused region-specific macrophages/microglia activation along spinothalamic and dorsal-column medial lemniscus pathways. A pro-inflammatory microglial marker was expressed in the spinal cord of injured rats compared to photobiomodulation-treated and sham group. Photobiomodulation-treated dorsal root ganglion macrophages expressed anti-inflammatory markers. Photobiomodulation effectively reduced mechanical hypersensitivity, potentially through modulating macrophage/microglial activation to an anti-inflammatory phenotype. Comment: The sham group refers to sham surgery, not sham treatment.
Brain Brain injury MicrogliosisKhuman2012J NeurotraumaLow-level laser light therapy improves cognitive deficits and inhibits microglial activation after controlled cortical impact in mice.MouseInjured mice treated with 60 J/cm² (500 mW/cm²×2 min) either transcranially or via an open craniotomy had modestly improved latency to the hidden platform (p<0.05 for group), and probe trial performance (p<0.01) compared to non-treated controls. The beneficial effects of LLLT in open craniotomy mice were associated with reduced microgliosis at 48 h (21.8±2.3 versus 39.2±4.2 IbA-1+ cells/200×field, p<0.05). Little or no effect of LLLT on post-injury cognitive function was observed using the other doses, a 4-h administration time point and 7-day administration of 60 J/cm². No effect of LLLT (60 J/cm² open craniotomy) was observed on post-injury motor function (days 1-7), brain edema (24 h), nitrosative stress (24 h), or lesion volume (14 days). Although further dose optimization and mechanism studies are needed, the data suggest that LLLT might be a therapeutic option to improve cognitive recovery and limit inflammation after TBI.
Oncology Tumor growth Mikhailov1993Investigations on the influence of low level diode laser irradiation of the growth of experimental tumors.MouseInvestigations on rats with an implanted tumour-carcinosarcoma of Walker (26 animals), cancer of the mammary glands, RMK-1 (75 animals) and in mice with spontaneous cancer of the mammary gland (188 animals)-have shown that the application of a low-level diode laser beam (890 nm) can effect the growth of the experimental tumour. Minimal doses produce a tumouro-static effect, while other doses produce different effects. Low level laser irradiation promotes dystrophic and necrotic changes in tumoural nodes.
Brain Alzheimers Disease Duggett & Chazot2014Biology and MedicineLow-Intensity Light Therapy (1068 nm) Protects CAD Neuroblastoma Cells from β-Amyloid-Mediated Cell DeathIn vitroIR1068 exposure was found to consistently significantly reduce cell death caused by Aβ, by up to 24%, over the range of Aβ concentrations (1-25 μM). The range of Aβ concentrations used would not necessarily be found in vivo. The use of IR1068 as a treatment for Alzheimer’s disease is under investigation, with recruitment of patients initiated in December 2010 (double-blind, placebo-controlled clinical trial). The results of these trials will enable statistically valid conclusions to be drawn, regarding the use of IR1068 as a treatment for neurodegenerative disease in a clinical setting. Note: OMICS International isnt a very respected scientific publishing company, but the article seems to be of decent quality.
Muscle Muscle injury Rodrigues2013J Photochem Photobiol BLow-level laser therapy (LLLT) (660nm) alters gene expression during muscle healing in rats.RatIrradiated groups presented less inflammatory process than control group after 14 and 21 days. Cox-2 levels were downregulated in all irradiated groups after 7, 14 and 21 days. On day 7, both treated groups had a downregulation of Vegf levels, and an upregulation after 14 and 21 days, mainly with 50J/cm(2). The MyoD levels were upregulated with high dose in all periods and with low dose after 21 days. Myogenin expression was downregulated in both treated groups after 7 days, and was upregulated with 10J/cm(2) after 21 days.
Cells Proliferation Biphasic dose responsePires-Oliveira2010Photomed Laser SurgLaser biomodulation on L 929 cell culture.Irradiation of L929 cells with pulsed laser in the near infrared region (904 nm) at two quite distinct energy densities allowed the observation of increased cell proliferation in both cases. The result was slightly higher for an energy density of 50 mJ=cm2 than for 6 J=cm2 , as demonstrated by fluorescence microscopy. Cell response was also found to be better 72 h after irradiation. Comment: The lower dose was more effective, even though the dose was 120-fold smaller (50mJ/cm2 vs 6J/cm2).
Diabetes mellitus Glycation Peplow & Baxter2013Lasers Surg MedTesting infrared laser phototherapy (810 nm) to ameliorate diabetes: irradiation on body parts of diabetic mice.MouseIrradiation of left inguinal region in diabetic mice with 810 nm laser has potential to ameliorate diabetes as shown by decreased blood plasma fructosamine. Comment: Irradiation of other parts wasnt helpful. The total effect is probably quite negligible.
Muscle Myopathy Mdx miceLeal-Junior2014PLoS OneSuperpulsed low-level laser therapy protects skeletal muscle of mdx mice against damage, inflammation and morphological changes delaying dystrophy progression.MouseIrradiation of superpulsed LLLT on successive days five times per week for 14 weeks decreased morphological changes, skeletal muscle damage and inflammation in mdx mice. This indicates that LLLT has potential to decrease progression of Duchenne muscular dystrophy. Star: The parameters were well reported, and the article was well written. A photograph of LLLT treatment was included.
Circulation Arterial restenosis Derkacz2013Lasers Med SciEffect of the intravascular low energy laser illumination during percutaneous coronary intervention on the inflammatory process in vascular wall.Human ControlledIrradiation of the lesion with low-energy laser radiation during the PCI procedure results in a decrease in the levels of pro-inflammatory IL 1β and IL 6 as well as in an increase in the levels of anti-inflammatory IL 10, which may result in decreased risk for restenosis.
Mechanisms Original research Isolated hepatocytesVacca1997Biochem Mol Biol IntThe irradiation of hepatocytes with He-Ne laser causes an increase of cytosolic free calcium concentration and an increase of cell membrane potential, correlated with it, both increases taking place in an oscillatory manner.In vitroIrradiation resulted in an enhancement in cytosolic free Ca2+ concentration that requires the presence of Ca2+ in the phase outside hepatocytes; consistently an increase in cell membrane potential was measured correlated with it.
Cells Nitric oxide Lindgård2007Lasers Med SciIrradiation at 634 nm releases nitric oxide from human monocytes.Irradiation resulted in elevated levels of NO but had no effect on iNOS or eNOS. Irradiation also caused a decrease in levels of intracellular ROS and had no effect on cell viability. Our studies indicate that irradiation at 634 nm releases NO, possibly from a preformed store, and reduces the production of intracellular ROS without affecting cell viability. Irradiation at 634 nm may have a wide range of clinical applications, including a reduction in oxidative stress-mediated injury in the vasculature. The intracellular ATP concentration was not significantly affected by irradiation (Fig. 5).
Eyes Mii2007J Nippon Med SchIncreases in central retinal artery blood flow in humans following carotid artery and stellate ganglion irradiation with 0.6 to 1.6 microm irradiation.HumanIrradiation to the [common carotid artery] produced a stronger effect than that to the SG in the ophthalmic artery (p=0.007) and central retinal artery (p=0.031).
Carpal tunnel Carpal tunnel syndrome Dincer2009Photomed Laser SurgThe effectiveness of conservative treatments of carpal tunnel syndrome: splinting, ultrasound, and low-level laser therapies.HumanIt appeared that the combinations of US or LLL therapy with splinting were more effective than splinting alone in treating CTS. However, LLL therapy plus splinting was more advantageous than US therapy plus splinting, especially for the outcomes of lessening of symptom severity, pain alleviation, and increased patient satisfaction.
Joints Osteoarthritis Youssef2016J Lasers Med SciEffect of Laser Therapy on Chronic Osteoarthritis of the Knee in Older Subjects.Human RCTIt can be concluded that addition of LLLT to exercise training program is more effective than exercise training alone in the treatment of older patients with chronic knee OA and the rate of improvement may be dose dependent, as with 6 J/cm(2) or 3 J/cm(2).
Wound healing Wounds Uzêda-E-Silva2016Lasers Med SciLaser phototherapy improves early stage of cutaneous wound healing of rats under hyperlipidic diet.RatIt can be concluded that the hyperlipidic diet modified the inflammation pattern in wound healing and that laser light has a positive biomodulative effect on the healing process only in early stages.
Muscle Muscle injury Ozaki2016Lasers Med SciAnalysis of photobiomodulation associated or not with platelet-rich plasma on repair of muscle tissue by Raman spectroscopy.RatIt is concluded that either PBM or PRP, and the association of both, was able to reduce the oxidative stress promoted by injury and modulate collagen production at the site of the injury. Furthermore, although both treatments individually were effective for repairing the damage caused by muscle injury, the association of both demonstrated a better histological aspect.
Bone Bone repair Dental titanium implant on the tibiaLopes2007Photomed Laser SurgInfrared laser photobiomodulation (lambda 830 nm) on bone tissue around dental implants: a Raman spectroscopy and scanning electronic microscopy study in rabbits.RabbitIt is concluded that infrared laser photobiomodulation does improve bone healing, and this may be safely assessed by Raman spectroscopy or SEM.
Oncology Tumor growth de C Monteiro2011Photomed Laser SurgInfluence of laser phototherapy (λ660 nm) on the outcome of oral chemical carcinogenesis on the hamster cheek pouch model: histological study.HamsterIt is concluded that LLLT, within the parameters used in the present study, caused a significant progression of the severity of SCC in the oral cavity of hamsters.
Heart CABG surgery Kazemi Khoo2014J Lasers Med SciApplication of Low-Level Laser Therapy Following Coronary Artery Bypass Grafting (CABG) Surgery.HumanIt is concluded that low-level laser irradiation after CABG surgery could decrease cardiac cellular damage and help accelerate the repair of cardiac tissue post-operatively. Comment: Parameters insufficiently reported.
Wound healing Wounds Cutaneous wound Healthy rats Iron-deficient rats LED phototherapy LED vs LLLTOliveira Sampaio2013Lasers Med SciEffect of laser and LED phototherapies on the healing of cutaneous wound on healthy and iron-deficient Wistar rats and their impact on fibroblastic activity during wound healing.RatIt is concluded that the use of LED light caused a significant positive biomodulation of fibroblastic proliferation on anemic animals and laser was more effective on increasing proliferation on non-anemics.
Heart MI MI AngiogenesisTuby2006Lasers Surg MedModulations of VEGF and iNOS in the rat heart by low level laser therapy are associated with cardioprotection and enhanced angiogenesis.RatIt is concluded that VEGF and iNOS expression in the infarcted rat heart is markedly upregulated by LLLT and is associated with enhanced angiogenesis and cardioprotection.
Oncology Tumor cells Pinheiro2002J Clin Laser Med SurgEffects of low-level laser therapy on malignant cells: in vitro study.In vitroIt is concluded, that irradiation with 670-nm laser light applied at doses between 0.04 and 4.810(4) Jm(-2) could significantly increase proliferation of laryngeal cancer cells.
Diabetes mellitus Góralczyk2016Lasers Med SciLow-level laser irradiation effect on endothelial cells under conditions of hyperglycemia.In vitroIt is considered that adverse effects of hyperglycemia on vascular endothelial cells may be corrected by the action of LLLT, especially with the wavelength of 830 nm. It leads to the reduction of TNF-α concentration in the supernatant and enhancement of cell proliferation.
Muscle Exercise Super Lizer™Demura2008J Hum Ergol (Tokyo)Effect of linear polarized near-infrared light irradiation on muscle fatigue recovery after repeated handgrip exercise.HumanIt is inferred that PL-irradiation maintains a high skin temperature and blood flow, but it may not contribute to recover muscle contraction performance in muscle fatigue.
LLLT: past and future Lubart1992J Photochem Photobiol BEffects of visible and near-infrared lasers on cell cultures.In vitro (fibroblasts)It is suggested that low-level laser therapy in the visible and in the near-infrared region is due to cell respiration stimulation by either the endogenous porphyrins in the cell, or by the cytochromes.
Bone Bone repair Surgical bone defect LED phototherapy Bone graft (HA + β-TCP)Soares2015Braz Dent JRepair of surgical bone defects grafted with hydroxylapatite + β-TCP and irradiated with λ=850 nm LED light.RatIt may be concluded that the use of LED phototherapy was effective in positively modulating the process of bone repair of bone defects in the femur of rats submitted or not to biomaterial grafting.
Muscle Muscle activity LED phototherapyKelencz2010Photomed Laser SurgEffect of low-power gallium-aluminum-arsenium noncoherent light (640 nm) on muscle activity: a clinical study.HumanIt was concluded that LED can be used as a clinical tool to increase muscle activity (1.044 J per point) and to prevent fatigue (2.088 J per point), without change in the muscle force.
Tendons Achilles tendon LED phototherapyHelrigle2016Lasers Med SciEffects of low-intensity non-coherent light therapy on the inflammatory process in the calcaneal tendon of ovariectomized rats.RatIt was concluded that low-intensity LED treatment using the parameters and wavelength of 945 nm in the time periods studied reduced the release of IL-6 and TNF-α and increased the release of IL-10, thereby improving the inflammatory response in OVX rats.
Tendons Achilles tendon Injury by contusionCasalechi2014Lasers Med SciAnalysis of the effect of phototherapy in model with traumatic Achilles tendon injury in rats.RatIt was concluded that treatment with LIL in the parameters used and the times studied reduces migration of inflammatory cells and improves the quality of repair while reducing the functional limitations.
Muscle Muscle injury CryoinjuryBaptista2011Photomed Laser SurgInfluence of laser photobiomodulation on collagen IV during skeletal muscle tissue remodeling after injury in rats.RatIt was demonstrated that LLLT promotes an increase in collagen IV immunolabeling in skeletal muscle in the first 7 days after acute trauma caused by cryoinjury, but does not modify the duration of the tissue-repair process. Even with LLLT, the injured muscle tissue needs ∼21 days to achieve the same state of organization as that in the noninjured muscle.
Oral Tooth extraction Wisdom tooth Intraoral+ExtraoralAras & Güngörmüş2009Photomed Laser SurgThe effect of low-level laser therapy on trismus and facial swelling following surgical extraction of a lower third molar.It was determined that the trismus and the swelling in LLLT group were significantly less than in the placebo group on postoperative days 2 and 7.
Muscle Muscle injury Avni2005Photomed Laser SurgProtection of skeletal muscles from ischemic injury: low-level laser therapy increases antioxidant activity.RatIt was found that laser irradiation markedly protects skeletal muscles from degeneration following acute I-R injury. This was evident by significantly (p < 0.05) higher content of creatine phosphokinase activity and lower (p < 0.05) activity of acid phosphatase in the LLLT-treated muscles relative to the injured non-irradiated ones. The content of antioxidants and heat shock proteins was also higher (p < 0.05) in the LLLT-treated muscles relative to that of injured non-irradiated muscles.
Joints Septic arthritis (experimental) Araujo2013ISRN RheumatolEffects of Low-Level Laser Therapy, 660 nm, in Experimental Septic Arthritis.RatIt was found that nociception increases in the right knee. There was a lack of results for the seeding of the synovial fluid. The morphological analysis showed slight recovery areas in the articular cartilage and synovia; however, there was the maintenance of the inflammatory infiltrate. The parameters used were not effective in the nociception reduction, even with the slight tissue recovery due to the maintenance of inflammatory infiltrate, but produced no change in the natural history of resolution of the infectious process.
Nerves PNS Marcolino2013J Hand MicrosurgAssessment of functional recovery of sciatic nerve in rats submitted to low-level laser therapy with different fluences. An experimental study: laser in functional recovery in rats.RatIt was possible to observe that the LLLT at fluency of 40 J/cm(2) and 80 J/cm(2) had a positive influence on the acceleration of the functional nerve recovery.
Wound healing Wounds Machneva2008Biozifika[A study of the effect of low-intensity laser radiation of the blue, green, and red spectral regions on the healing of experimental skin wounds in rats]. [Article in Russian]RatIt was shown that irradiation with laser accelerated the healing of wounds in all cases. The exposure to laser radiations in the red (1.5 J/cm), blue, and green (0.75 J/cm2) spectral regions shortened the time of wound healing from 22 to 17 and 19 days, respectively.
LLLT: past and future Mester1968Langenbecks Arch Chir[Studies on the inhibiting and activating effects of laser beams]. [Article in German]In vitro & in vivo ??Laser beams of low energy were tested on four biological systems and were found to promote the cell functions. Higher radiant energy causes inhibition. Repeated small doses of radiation have a cumulative effect. The knowledge of these facts is essential if any therapeutic use is intended. Original title: Untersuchungen über die hemmende bzw. fördernde Wirkung der Laserstrahlen Comment: It is nice that parameters were considered already in the sixties!
Liver Liver regeneration Hepatectomy -> Liver regenerationOliveira2006Acta Cir BrasThe effect of laser on remanescent liver tissue after 90% hepatectomy in rats.RatLaser did not cause hepatic injuries additional to the partial hepatectomy and perhaps led to a benefit by stimulating the proliferative activity. Comment: Parameters were poorly reported.
Muscle Exercise Biphasic dose responseLopes-Martins2006J Appl Physiol (1985)Effect of low-level laser (Ga-Al-As 655 nm) on skeletal muscle fatigue induced by electrical stimulation in rats.RatLaser groups receiving 0.5 and 1.0 J/cm2 showed significant increases in mean performed work compared with both the control group and their first contraction values.
Wound healing Burns 3rd degree burnFiório2014Lasers Med SciEffect of low-level laser therapy on types I and III collagen and inflammatory cells in rats with induced third-degree burns.RatLaser irradiation (both 3 and 4 J/cm(2)) resulted in reduction in the inflammatory process and improved collagen deposition, thereby ameliorating the healing of third-degree burns.
Circulation Angiogenesis Myocardial infarctionMirsky2002Antioxid Redox SignalPromotion of angiogenesis by low energy laser irradiation.RatLaser irradiation caused a 3.1-fold significant increase in newly formed blood vessels 6 days post infarction, as compared with nonirradiated rats.
Pain Nociception Saphenous nerveSato1994Acupunct Electrother ResGa-Al-As laser irradiation inhibits neuronal activity associated with inflammation.RatLaser irradiation inhibited both the asynchronous firing by that was induced by turpentine and increased part of the slow components of the action potentials. Thus, the laser irradiation selectively inhibited nociceptive signals at peripheral nerves.
Joints Usuba1998Lasers Surg MedEffect of low-level laser therapy (LLLT) on viscoelasticity of the contracted knee joint: comparison with whirlpool treatment in rats.RatLaser irradiation showed no significant changes except the phase-lag of laser 60 mW. Under the conditions of this study, LLLT stimulation did not provide a significant effect for minimizing the degree of experimental joint contracture over whirlpool treatment.
Oral Nerves Wakabayashi1993Lasers Surg MedEffect of irradiation by semiconductor laser on responses evoked in trigeminal caudal neurons by tooth pulp stimulation.RatLaser irradiation suppressed the late discharges in the response of the caudal neurons which were evoked by excitatory inputs from C-fiber afferents, but did not suppress the early discharges evoked by inputs from A delta-fiber afferents. These results suggest that low power laser irradiation has a suppressive effect on injured tissue by blocking the depolarization of C-fiber afferents.
Wound healing Wounds Diabetic rats Dose response (?)Dadpay2012J Photochem Photobiol BEffects of pulsed infra-red low level-laser irradiation on open skin wound healing of healthy and streptozotocin-induced diabetic rats by biomechanical evaluation.RatLaser irradiation with 0.03J/cm(2) significantly decreased the maximum load for wound repair in healthy rats (p=0.015). Laser irradiation with 0.2J/cm(2) significantly increased the maximum load in wounds from the healthy control (p=0.021) and diabetic (p<001) groups. Laser treatments with a pulsed infrared laser at 0.2J/cm(2) significantly accelerated wound healing in both healthy and diabetic rats.
Wound healing Wounds Solmaz2016Lasers Med SciLaser biostimulation of wound healing: bioimpedance measurements support histology.RatLaser irradiations of both energy densities stimulated the wound healing process. In particular, laser irradiation of lower energy density had more evidence especially for the first days of healing process. On the 7th day of healing, 3 J/cm2 laser-irradiated tissues had significantly smaller wound areas compared to non-irradiated wounds (p < 0.05). The electrical impedance results supported the idea of laser biostimulation on healing of cutaneous skin wounds. Thus, bioimpedance measurements may be considered as a non-invasive supplementary method for following the healing process of laser-irradiated tissues. Comment: On the 10th day, the wound area was smaller in the control group, compared to the irradiated groups...
Oral Oral mucositis Arora2008Oral Surg Oral Med Oral Pathol Oral Radiol EndodEfficacy of He-Ne Laser in the prevention and treatment of radiotherapy-induced oral mucositis in oral cancer patients.HumanLaser therapy applied prophylactically during radiotherapy can reduce the severity of oral mucositis, severity of pain, and functional impairment.
Pain Analgesia Formalin injection to pawPozza2008Med Oral Patol Oral Cir BucalAnalgesic action of laser therapy (LLLT) in an animal model.MouseLaser therapy had an analgesic effect and red laser had the best results.
Bone Bone repair Systemic effects?Batista2015Lasers Med SciLow-level laser therapy on bone repair: is there any effect outside the irradiated field?RatLaser therapy presented a positive local biostimulative effect in the early stage of bone healing, but the LLLT effect was not observed a long distance from the evaluated area.
Oral Oral mucositis Oton-Leite2012Head NeckEffect of intraoral low-level laser therapy on quality of life of patients with head and neck cancer undergoing radiotherapy.Human RCTLaser therapy reduces the impact of radiotherapy on the QOL of patients with head and neck cancer. Comment: The parameters were poorly reported.
Nerves Diabetic neuropathy Bashiri H2013Acta Med IranEvaluation of low level laser therapy in reducing diabetic polyneuropathy related pain and sensorimotor disorders.Human RCTLaser therapy resulted in improved neuropathy outcomes in diabetic patients who received it relative to the group that received sham therapy, evaluating before and after LLLT assessments. Comment: A poorly written paper.
Respiratory system COPD Aksenova & Burduli2016Ter Arkh[Pathogenetic effects of low-intensity laser therapy for chronic obstructive pulmonary disease]. [Article in Russian]HumanLaser therapy used in the combination treatment of patients with COPD promotes correction of the typical pathological processes.
Pain Zarković1989Lasers Surg MedEffect of semiconductor GaAs laser irradiation on pain perception in mice.MouseLaser treatment induced further shortening of latencies, suggesting its stimulatory influence on pain perception. Note: There is no reason to believe that this ultra-low dose of 0.41 mJ/cm2 would have had any biological effects.
Lymphedema Ahmed Omar2011J Surg ResTreatment of post-mastectomy lymphedema with laser therapy: double blind placebo control randomized study.Human RCT/DBLaser treatment was found to be effective in reducing the limb volume, increase shoulder mobility, and hand grip strength in approximately 93% of patients with postmastectomy lymphedema.
Joints Osteoarthritis Papain-induced joint inflammation Biphasic dose responseAlves2013Arthritis Res TherEffect of low-level laser therapy on the expression of inflammatory mediators and on neutrophils and macrophages in acute joint inflammation.RatLaser treatment with 50 mW was more efficient than 100 mW in reducing cellular inflammation, and decreased the expression of IL-1β and IL-6. However, the 100 mW treatment led to a higher reduction of TNFα compared with the 50 mW treatment. Star: In this paper, parameters are nicely reported in a table.
Wound healing Wounds LLLT vs dexamethasoneMarchionni2010Photomed Laser SurgInfluence of laser (λ670 nm) and dexamethasone on the chronology of cutaneous repair.RatLaser was effective in reducing swelling and polymorphonuclear cells and accelerated tissue repair, even in the presence of dexamethasone.
Mechanisms Original research TGF-β1 Periodontium & peri-implantitisTang2016J Periodontal ResLaser-activated transforming growth factor-β1 induces human β-defensin 2: implications for laser therapies for periodontitis and peri-implantitis.In vitroLaser-activated TGF-β1 signaling and induced expression of HBD-2, both of which are individually capable of promoting healing in tissues adjacent to high-power surgical laser applications.
Respiratory system Lung inflammation Allergic lung inflammationCosta Carvalho2016J BiophotonicsThe chemokines secretion and the oxidative stress are targets of low-level laser therapy in allergic lung inflammation.Laser-treated allergic mice presented reduction of both the ICAM-1 and eosinophil in the lungs. RANTES, CCL8, CCL3 and eotaxins were reduced in BALF of laser-treated allergic mice. In allergic mice lung LLLT decreased the CCR1 and CCR3 and restored the oxidative stress balance as well. Laser decreased the lipidic peroxidation in allergic mice lung as much as increased SOD, GPx and GR. It shows that LLLT on allergic lung inflammation involves leukocyte-attractant chemokines and endogenous antioxidant. Based on results, LLLT may ultimately become a non- invasive option in allergic lung disease treatment. Comment: The parameters were well reported.
Bone Bone repair Mota2013Res Vet SviLow-power laser therapy for repairing acute and chronic-phase bone lesions.RatLaser-treated animals showed significant increases in serum alkaline phosphatase levels and had an effect on biomechanical property, resulting in a gradual increase in bone stiffness. Laser therapy aided the bone consolidation process and favored the physiopathologic mechanisms involved in bone tissue repair, and its effects were more prominent when treatment started during the acute phase of the injury.
Heart MI MIWhittaker & Patterson2000Lasers Surg MedVentricular remodeling after acute myocardial infarction: effect of low-intensity laser irradiation.RatLaser-treated fibroblasts occupied more area than controls. Hearts receiving the 10 mW treatment had smaller volumes than sham hearts. Laser treatment reduced infarct thinning and preserved arterial lumen area; however, collagen was not increased and inflammation was inhibited.
Protozoa Paramecium Calcium release by 980nmAmaroli2016Photochem PhotobiolPhotobiomodulation by Infrared Diode-Laser: Effects on Intracellular Calcium Concentration and Nitric Oxide Production of Paramecium.ProtozoaLastly, the 980nm and 64J/cm2 or 96J/cm2 were the only parameters to induce a release of stored calcium.
Pain Analgesia Wedlock1996Physiol BehavAnalgesic effects of cranial laser treatment in two rat nociception models.RatLatency to lick hind paws on the hot plate was highly significantly prolonged by laser treatment across all doses and time periods, F(4, 126) = 4.51, p < 0.01. There was good dose dependency for immediate observations, but at 24 h 18 J/cm2 was the most effective dose. Laser treatment also delayed tail flick responses at both doses and all time periods, F(2, 54) = 10.60, p < 0.001, but 12 and 18 J/cm2 doses were similar in efficacy.
Tendons Achilles tendon LED phototherapyXavier2014Lasers Med SciLow-level light-emitting diode therapy increases mRNA expressions of IL-10 and type I and III collagens on Achilles tendinitis in rats.RatLED (880 nm) was effective in increasing mRNA expression of IL-10 and type I and III collagen. Therefore, LED therapy may have potentially therapeutic effects on Achilles tendon injuries.
Dermatology Radiation dermatitis Fife2010Dermatol SurgA randomized, controlled, double-blind study of light emitting diode photomodulation for the prevention of radiation dermatitis in patients with breast cancer.Human RCT/DBLED photomodulation did not reduce the incidence of radiation-induced skin reactions or interruptions in therapy. . Note: DeLand published a letter, wondering why the results were so different in this study. He suggests it might be related to the treatment parameters... Metelitsas commentary also mentions this issue, and also focuses on some differences between the treatments in these two studies.
Skin Weiss2005Dermatol SurgClinical experience with light-emitting diode (LED) photomodulation.Case seriesLED photomodulation has been used alone for skin rejuvenation in over 300 patients but has been effective in augmentation of results in 600 patients receiving concomitant nonablative thermal and vascular treatments such as intense pulsed light, pulsed dye laser, KTP and infrared lasers, radiofrequency energy, and ablative lasers. LED photomodulation reverses signs of photoaging using a new nonthermal mechanism. The anti-inflammatory component of LED in combination with the cell regulatory component helps improve the outcome of other thermal-based rejuvenation treatments.
Kidney Meckel syndrome Meckel syndrome LED phototherapyLim2011Nephron ExtraAcceleration of the meckel syndrome by near-infrared light therapy.RatLED phototherapy initiated after the onset of symptoms was detrimental to MKS-induced pathology. NIR stimulates CCO thereby increasing the kidneys need for oxygen. We hypothesize that cystic compression of the vasculature impairs oxygen availability and the enhanced CCO activity produces more radicals, which are not sufficiently detoxified by the increased CAT activity.
Oral Oral mucositis LED phototherapyWhelan2001J Clin Laser Med SurgEffect of NASA light-emitting diode irradiation on wound healing.HumanLED produced a 47% reduction in pain of children suffering from oral mucositis.
Muscle Muscle injury Cryoinjury LED phototherapyde Melo2016Lasers Med SciLight-emitting diode therapy increases collagen deposition during the repair process of skeletal muscle.RatLED therapy at 850 nm induced a significant reduction in inflammation, decreased MMP-2 activity, and increased the amount of immature muscle and collagen fibers during the muscle repair process following acute injury.
Development Embryogenesis Yeager2006Photomed Laser SurgSurvivorship and mortality implications of developmental 670-nm phototherapy: dioxin co-exposure.ChickenLED therapy decreased the embryonic mortality rate by 41%, resulting in increased embryonic survival and improved hatching success in eggs exposed to 200 ppt dioxin. However, at sub-lethal dioxin concentrations and in oil-treated controls, LED therapy slightly increased mortality.
Wound healing Wounds LED phototherapyDungel2014Lasers Surg MedLow level light therapy by LED of different wavelength induces angiogenesis and improves ischemic wound healing.RatLED therapy with both wavelengths significantly increased angiogenesis in the sub-epidermal layer and intramuscularly (panniculus carnosus muscle) which was associated with significantly improved tissue perfusion 7 days after the ischemic insult. Accordingly, tissue necrosis was significantly reduced and shrinkage significantly less pronounced in the LED-treated groups of both wavelengths.
Muscle Energy metabolism Ferraresi2015Photochem PhotobiolLow-level laser (light) therapy increases mitochondrial membrane potential and ATP synthesis in C2C12 myotubes with a peak response at 3-6 h.In vitro C2C12 myotubesLEDT employed a cluster of LEDs with 20 red (630 ± 10 nm, 25 mW) and 20 near-infrared (850 ± 10 nm, 50 mW) delivering 28 mW cm(2) for 90 s (2.5 J cm(2)) with analysis at 5 min, 3 h, 6 h and 24 h post-LEDT. LEDT-6 h had the highest MMP, followed by LEDT-3 h, LEDT-24 h, LEDT-5 min and Control with significant differences. The same order (6 h > 3 h > 24 h > 5 min > Control) was found for ATP with significant differences. A good correlation was found (r = 0.89) between MMP and ATP. These data suggest an optimum time window of 3-6 h for LEDT stimulate muscle cells. Comment: The increase in ATP levels at 6h was quite huge. Interesting.
Muscle Exercise LED phototherapy LED clusterFerraresi2015Physiother Theory PractMuscular pre-conditioning using light-emitting diode therapy (LEDT) for high-intensity exercise: a randomized double-blind placebo-controlled trial with a single elite runner.Human (n=1)LEDT improved the speed of the muscular VO2 adaptation (∼-9 s), decreased O2 deficit (∼-10 L), increased the VO2 from the slow component phase (∼+348 ml min(-1)), and increased the time limit of exercise (∼+589 s). Note: A photograph is supplied, but it is black-and-white.
Pain Hyperalgesia Chronic inflammatory hyperalgesia induced by Complete Freunds Adjuvant (CFA) LED phototherapy Dose responseMartins2016NeuroscienceLight-emitting diode therapy reduces persistent inflammatory pain: Role of interleukin 10 and antioxidant enzymes.MouseLEDT inhibited mechanical and thermal hyperalgesia induced by CFA injection. LEDT did not reduce paw edema, neither influenced the levels of TNF-α and IL1-β; although it increased the levels of IL-10. LEDT significantly prevented TBARS increase in both acute and chronic phases post-CFA injection; whereas protein carbonyl levels were reduced only in the acute phase. LEDT induced an increase in both SOD and CAT activity, with effects observable in the acute but not in the chronic. And finally, pre-administration of naloxone or fucoidin prevented LEDT analgesic effect.
Muscle Exercise LED phototherapy LED clusterFerraresi2015Lasers Med SciLight-emitting diode therapy (LEDT) before matches prevents increase in creatine kinase with a light dose response in volleyball players.Human RCT/DBLEDT prevented significant increases of CK in blood in athletes when applied before official matches with a light dose response of 210-315 J, suggesting athletes might consider applying LEDT before competition. Nampo et al published a brief criticism of this paper: Due to the fragilities we pointed above, we agreed that the validity of this paper does not allow safe conclusions. To produce valid and meaningful results, we recommend to increase sample size, evaluate functional outcomes to establish clinical relevance, evaluate better established indicators of muscle damage (i.e., imaging), and do better data reporting.
Muscle Exercise LED cluster (34+35)Baroni2010Photomed Laser SurgEffect of light-emitting diodes therapy (LEDT) on knee extensor muscle fatigue.Human RCT/DB CrossoverLEDT treatment produced a smaller maximal isometric torque decrease after high-intensity concentric isokinetic exercise, which is consistent with an increase in performance.
Muscle Exercise LED phototherapy LED clusterFerraresi2015Lasers Med SciTime response of increases in ATP and muscle resistance to fatigue after low-level laser (light) therapy (LLLT) in mice.MouseLEDT-6 h was the subgroup with the highest ATP content in soleus and gastrocnemius compared to all subgroups (P < 0.001). In addition, mice in LEDT-6 h group performed more repetitions in the fatigue test (P < 0.001) compared to all subgroups: LEDT-sham and LEDT-5 min (~600 %), LEDT-3 h (~200 %), and LEDT-24 h (~300 %). A high correlation between the fatigue test repetitions and the ATP content in soleus (r = 0.84) and gastrocnemius (r = 0.94) muscles was observed. LEDT increased ATP content in muscles and fatigue resistance in mice with a peak at 6 h. Although the time response in mice and humans is not the same, athletes might consider applying LEDT at 6 h before competition.
Cells Proliferation HIG-82 rabbit synovial fibroblastsTaniguchi2009Lasers Surg MedLow-energy laser irradiation promotes synovial fibroblast proliferation by modulating p15 subcellular localization.In vitroLELI promoted HIG-82 synovial fibroblast proliferation and induced cytoplasmic localization of cyclin-dependent kinase inhibitor p15 (INK4B/CDKN2B). Our findings suggest that cAMP may be involved in the effect of LELI on synovial fibroblast proliferation.
Skin Acne vulgaris LED phototherapy (w/ blue light)Sadick NS2008J Drugs DermatolHandheld LED array device in the treatment of acne vulgaris.HumanLesion counts progressively reduced throughout the 4-week light therapy period and continued to reduce up to 8 weeks posttherapy, with a final average reduction of 69% seen 8 weeks after the treatment course (P>.001). This pattern is similar to previously reported studies.
Immunity Sepsis Yu1997Lasers Surg MedImprovement of host response to sepsis by photobiomodulation.RatLI significantly improved ex-vivo lymphocyte proliferation of cells from septic rats (179.7 +/- 17.2 vs. 129.5 +/- 7.8; P < 0.01) and enhanced survival in septic rats (79% vs. 42%; P < 0.001). LI significantly stimulated lymphocyte proliferation in the presence of mitogenic stimuli and enhanced lymphocyte ATP synthesis (P < 0.05). LI improves the host immune response and survival rate in sepsis in an animal model. Our studies suggest that LI may be useful as an adjuvant therapy for sepsis.
Cells Energy metabolism Biphasic dose responseSharma2011Lasers Surg MedDose response effects of 810 nm laser light on mouse primary cortical neurons.Light induced a significant increase in calcium, ATP and MMP at lower fluences and a decrease at higher fluences. The results suggest that LLLT at lower fluences is capable of inducing mediators of cell signaling processes which in turn may be responsible for the beneficial stimulatory effects of the low level laser. At higher fluences beneficial mediators are reduced and high levels of Janus-type mediators such as ROS and NO (beneficial at low concentrations and harmful at high concentrations) may be responsible for the damaging effects of high-fluence light and the overall biphasic dose response.
Nerves PNS Nerve conduction LED phototherapy LED clusterTelemeco & Schrank2013J Lasers Med SciThe Effect of Light Therapy on Superficial Radial Nerve Conduction Using a Clustered Array of Infrared Super luminous Diodes and Red Light Emitting Diodes.Human RCT/SBLight irradiation using a cluster probe containing infrared super luminous and red light emitting diodes does not impact the neurophysiological properties of the superficial radial nerve.
Liver Diabetes Diabetic rats LED phototherapyLim2009J Biochem Mol ToxicolEffects of low-level light therapy on hepatic antioxidant defense in acute and chronic diabetic rats.RatLight treatment was ineffective as an antioxidant therapy in chronic diabetes, but light treatment for 18 days in acutely diabetic rats resulted in the normalization of hepatic glutathione reductase and superoxide dismutase activities and a significant increase in glutathione peroxidase and glutathione-S transferase activities. The results of this study suggest that 670 nm photobiomodulation may reduce, at least in part, acute hepatic oxidative stress by enhancing the antioxidant defense system in the diabetic rat model. Light therapy also didnt affect blood glucose levels. ATP and CCO activity were increased.
Gene expression Masha2013Photomed Laser SurgLow-intensity laser irradiation at 660 nm stimulates transcription of genes involved in the electron transport chain.LILI upregulated cytochrome c oxidase subunit VIb polypeptide 2 (COX6B2), cytochrome c oxidase subunit VIc (COX6C), and pyrophosphatase (inorganic) 1 (PPA1) in diabetic wounded cells; COX6C, ATP synthase, H+transporting, mitochondrial Fo complex, subunit B1 (ATP5F1), nicotinamide adenine dinucleotide (NADH) dehydrogenase (ubiquinone) 1 alpha subcomplex, 11 (NDUFA11), and NADH dehydrogenase (ubiquinone) Fe-S protein 7 (NDUFS7) in wounded cells; and ATPase, H+/K+ exchanging, beta polypeptide (ATP4B), and ATP synthase, H+ transporting, mitochondrial Fo complex, subunit C2 (subunit 9) (ATP5G2) in ischemic cells. LILI at 660 nm stimulates the upregulation of genes coding for subunits of enzymes involved in complexes I and IV and ATP synthase.
Opioid withdrawal Morphine Ojaghi2014Lasers Med SciRole of low-intensity laser therapy on naloxone-precipitated morphine withdrawal signs in mice: is nitric oxide a possible candidate mediator?MouseLILT and L-NAME (20, 50, and 100 mg/kg) per se significantly decreased escape jump count and stool weight in morphine-dependent naloxone-treated mice (p < 0.01). Coadministration of LILT and L-NAME (20, 50, and 100 mg/kg) also reduced escape jump and stool weight (p < 0.05) but with no synergetic or additive response. Here, LILT at this fluence may show its maximal effects on NO and therefore no noticeable effects appeared during coadministration use. Moreover, LILT and L-NAME follow the same track of changes in escape jump and stool weight. Conceivably, it seems that LILT acts partly via NO system, but the exact path is still obscure and rather intricate. The precise mechanisms need to be clarified.
Respiratory system Lung inflammation Acute lung inflammationMafra de Lima2010J Photochem Photobiol BLow intensity laser therapy (LILT) in vivo acts on the neutrophils recruitment and chemokines/cytokines levels in a model of acute pulmonary inflammation induced by aerosol of lipopolysaccharide from Escherichia coli in rat.RatLILT inhibited pulmonary edema and endothelial cytoskeleton damage, as well as neutrophil influx and activation. Similarly, the LILT reduced the TNF-α and IL-1β, in lung and BALF. LILT prevented lung ICAM-1 up-regulation. The rise of CINC-1 and MIP-2 protein levels in both lung and BALF, and the lung mRNA expressions for IL-10, were unaffected. Data suggest that the LILT effect is due to the inhibition of ICAM-1 via the inhibition of TNF-α and IL-1β.
Bone Bone repair Kocyigit2012Photomed Laser SurgA comparison of the low-level laser versus low intensity pulsed ultrasound on new bone formed through distraction osteogenesis.RabbitLIPUS and LLLT applied during the distraction period accelerated the DO treatment.
Brain Alzheimers Disease Beta-amyloid injection to hippocampusLu2017Neurobiol AgingLow-level Laser Therapy for Beta-Amyloid Toxicity in Rat HippocampusRatLLI treatment suppressed Aβ-induced hippocampal neurodegeneration and long-term spatial and recognition memory impairments. Molecular studies revealed that LLI treatment: a) restored mitochondrial dynamics, by altering fission and fusion protein levels thereby suppressing Aβ-induced extensive fragmentation; b) suppressed Aβ-induced collapse of mitochondrial membrane potential; c) reduced oxidized mtDNA and excessive mitophagy; d) facilitated mitochondrial homeostasis via modulation of the Bax/Bcl-2 ratio and of mitochondrial antioxidant expression; e) promoted cytochrome c oxidase activity and ATP synthesis; f) suppressed Aβ induced G6PDH and NADPH oxidase activity; g) enhanced the total antioxidant capacity of hippocampal CA1 neurons while reducing oxidative damage; and h) suppressed Aβ-induced reactive gliosis, inflammation and tau hyperphosphorylation.
Toxins Snake venom LLLT+LED LLLT vs LED LED phototherapyNadur-Andrade2014Photochem Photobiol SciPhotobiostimulation reduces edema formation induced in mice by Lys-49 phospholipases A2 isolated from Bothrops moojeni venom.MouseLLL and LED irradiation significantly reduced the edema formation by both myotoxins from 1 up to 6 hours after the injection. Both LLL and LEDs were similar in reducing the edema formation induced by myotoxins. The combined photobiostimulation with antivenom had the same effect in reducing edema as treatment with the LLL or LEDs alone.
Circulation Aneurysm Ang-II-infused Apo-E(-/-) miceGavish2014Lasers Surg MedArrest of progression of pre-induced abdominal aortic aneurysm in apolipoprotein E-deficient mice by low level laser phototherapy.MouseLLL not only prevents de novo development of AAA, but, from this study, also arrests further progression of pre-induced AAA and its associated deterioration in the biomechanical integrity of the aortic wall in Apo-E(-/-) mice.
Oral Oral mucositis Patients with head/neck cancer (chemoradiotherapy)Gouvêa de Lima2012Int J Radiat Oncol Biol PhysOral mucositis prevention by low-level laser therapy in head-and-neck cancer patients undergoing concurrent chemoradiotherapy: a phase III randomized study.Human RCT/DBLLL therapy was not effective in reducing severe oral mucositis, although a marginal benefit could not be excluded. It reduced RT interruptions in these head-and-neck cancer patients, which might translate into improved CRT efficacy.
Circulation Microcirculation Mesenteric circulation Dose responseMaegawa2000Lasers Surg MedEffects of near-infrared low-level laser irradiation on microcirculation.RatLLLI caused potent dilation in the laser-irradiated arteriole, which led to marked increases in the arteriolar blood flow. The circulatory changes observed seemed to be mediated largely by LLLI-induced reduction of [Ca2+]i in VSMCs, in addition to the involvement of NO in the initial phase.
Heart MI MIYang2013Photomed Laser SurgEffect of low-level laser irradiation on oxygen free radicals and ventricular remodeling in the infarcted rat heart.RatLLLI could cause OFR accumulation, reduce infarct size, increase ventricular wall thickness, and attenuate the formation of collagen fibers, suggesting the beneficial effects of LLLI on improvement of VR after MI.
Immunity Macrophages Gavish2008Lasers Surg MedIrradiation with 780 nm diode laser attenuates inflammatory cytokines but upregulates nitric oxide in lipopolysaccharide-stimulated macrophages: implications for the prevention of aneurysm progression.In vitroLLLI reduced gene expression of MCP-1, IL-1alpha, IL-10 (P<0.01), IL-1beta, and IL-6 (P<0.05) when cells were stimulated by 1 microg/ml LPS. LLLI reduced LPS-induced secretion of MCP-1 over non-irradiated cells by 17+/-5% and 13+/-5% at 12 hours (0.1 and 1 microg/ml LPS; P<0.01 and P=0.05, respectively), and reduced IL-1beta by 22+/-5% and 25+/-9% at 24 hours (0.1 and 1 microg/ml LPS, P=0.01 and P=0.06, respectively). These properties of LLLI [...] may be of profound therapeutic relevance for arterial diseases such as aneurysm where inflammatory processes and weakening of the matrix structure of the arterial wall are major pathologic components.
Circulation Smooth muscle cells Gavish2006Lasers Surg MedLow-level laser irradiation modulates matrix metalloproteinase activity and gene expression in porcine aortic smooth muscle cells.In vitroLLLI stimulates SMC proliferation, stimulates collagen synthesis, modulates the equilibrium between regulatory matrix remodeling enzymes, and inhibits pro-inflammatory IL-1-beta gene expression. These findings may be of therapeutic relevance for arterial diseases such as aneurysm where SMC depletion, weakened extracellular matrix, and an increase in pro-inflammatory markers are major pathologic components.
Oral Tissue engineering Pulp stem cells Bioceramic scaffoldsTheocharidou2016Lasers Med SciOdontogenic differentiation and biomineralization potential of dental pulp stem cells inside Mg-based bioceramic scaffolds under low-level laser treatment.In vitroLLLI treatment proved to be beneficial for odontogenic differentiation and biomineralization of DPSCs inside the bioceramic scaffolds, making this therapeutic modality promising for targeted dentin engineering.
Respiratory system Lung inflammation Tracheal and lung function after intestinal I/Rde Lima2013Lasers Med SciSuppressive effect of low-level laser therapy on tracheal hyperresponsiveness and lung inflammation in rat subjected to intestinal ischemia and reperfusion.RatLLLT (660 nm, 7.5 J/cm(2)) restored the tracheal hyperresponsiveness and hyporesponsiveness in all the periods after intestinal reperfusion. Although LLLT reduced edema and MPO activity, it did not do so in all the postreperfusion periods. It was also observed with the ICAM-1 expression. In addition to reducing both TNF-α and iNOS, LLLT increased IL-10 in the lungs of animals subjected to i-I/R. The results indicate that LLLT can control the lungs inflammatory response and the airway reactivity dysfunction by simultaneously reducing both TNF-α and iNOS.
Edema Paw Carrageenan-induced paw edemaPrianti2014Lasers Med SciLow-level laser therapy (LLLT) reduces the COX-2 mRNA expression in both subplantar and total brain tissues in the model of peripheral inflammation induced by administration of carrageenan.RatLLLT (7.5 J/cm(2)) reduced significantly the COX-2 mRNA expression both in the subplantar (~2.5-fold) and brain (4.84-9.67-fold) tissues. The results show that LLLT is able to reduce COX-2 mRNA expression. It is possible that the mechanism of LLLT decreasing hyperalgesia is also related to its effect in reducing the COX-2 expression in the CNS.
Muscle Muscle injury Silveira2013Lasers Med SciEffects of low-level laser therapy (GaAs) in an animal model of muscular damage induced by trauma.RatLLLT accelerated the muscular healing by significantly decreasing superoxide anion production, TBARS levels, the activity of SOD, and hydroxyproline content. The data strongly indicate that increased ROS production and augmented collagen synthesis are elicited by traumatic muscular injury, effects that were significantly decreased by LLLT.
Respiratory system Pleurisy Biphasic dose responseLopes-Martins2005Photomed Laser SurgSpontaneous effects of low-level laser therapy (650 nm) in acute inflammatory mouse pleurisy induced by carrageenan.MouseLLLT administered at 1-3 h after the induction of inflammatory pleurisy significantly reduces the inflammatory cell migration measured. Under these conditions and at 2.5 mW, 7.5 J/cm(2) was more effective than 3 J/cm(2) and 15 J/cm(2).
Wound healing Wounds Surgical wound Edema LLLT vs dexamethasoneReis2008Photomed Laser SurgEffect of 670-nm laser therapy and dexamethasone on tissue repair: a histological and ultrastructural study.RatLLLT alone accelerates post-surgical tissue repair and reduces edema and the polymorphonuclear infiltrate even in the presence of dexamethasone.
Immunity Macrophages (alveolar) Souza2014J Photochem Photobiol BLow-level laser therapy suppresses the oxidative stress-induced glucocorticoids resistance in U937 cells: relevance to cytokine secretion and histone deacetylase in alveolar macrophages.In vitroLLLT and dexa inhibited the LPS-stimulated U937 cells cytokines, but dexa effect disappeared with H2O2. With TSA, the LLLT was less effective on H2O2/LPS stimulated- U937 cells cytokines. Dexa failed on H2O2/LPS- induced HDAC, while LLLT restored the HDAC and the dexa effect. LLLT plus prostaglandin E2 (PGE2) increased cyclic adenosine monophosphate (cAMP) and potentiated the laser action on oxidative stress-induced cytokine. LLLT reduced the PI3K and its effects on cytokine and HDAC was suppressed with LY294002. In situations of corticoid resistance, LLLT acts decreasing the cytokines and HDAC through the activation of the protein kinase A via the inhibition of PI3K.
Nerves PNS Dias2015J Neurol SciMorphometric and high resolution scanning electron microscopy analysis of low-level laser therapy and latex protein (Hevea brasiliensis) administration following a crush injury of the sciatic nerve in rats.RatLLLT and F1 resulted in structural nerve improvements after 4 or 8 weeks of injury. In general only F1 protein was more effective compared to LLLT and LLLT + F1
Wound healing Surgical wounds LLLT vs LED LED phototherapyLima2017Photomed Laser SurgPhotobiomodulation (Laser and LED) on Sternotomy Healing in Hyperglycemic and Normoglycemic Patients Who Underwent Coronary Bypass Surgery with Internal Mammary Artery Grafts: A Randomized, Double-Blind Study with Follow-Up.Human RCT/DB (?)LLLT and LED groups had similarly less hyperemia and less incision bleeding or dehiscence (p ≤ 0.005) and the outcomes were also analogous between hyperglycemic and normoglycemic patients, which indicates no difference observed in an intragroup analysis (p ≥ 0.05).
Wound healing Surgical wounds LLLT vs LED LED phototherapyLima2016Photomed Laser SurgLow-Level Laser and Light-Emitting Diode Therapy for Pain Control in Hyperglycemic and Normoglycemic Patients Who Underwent Coronary Bypass Surgery with Internal Mammary Artery Grafts: A Randomized, Double-Blind Study with Follow-Up.Human RCT/DBLLLT and LED had similar analgesic effects in hyperglycemic and normoglycemic patients, better than placebo and control groups.
Heart MI MI Systemic effectBlatt2016Photomed Laser SurgLow-Level Laser Therapy to the Bone Marrow Reduces Scarring and Improves Heart Function Post-Acute Myocardial Infarction in the Pig.PigLLLT application to BM in the porcine model for MI caused a significant reduction in scarring, enhanced angiogenesis and functional improvement both in the acute and long term phase post-MI.
Muscle Muscle injury Ribeiro2015 epubLasers Surg MedThe effect of low-level laser therapy (LLLT) applied prior to muscle injury.RatLLLT applied prior to muscle injury led to a reduction in myonecrosis and inflammatory cells, an increase of blood vessels and immature muscle fibers. An increase in MMP-2 activity and a decrease in collagen deposition were also found, with a better collagen organization and distribution. LLLT applied immediately prior to injury had positive effects during the muscle regeneration process. Star: Parameters were well reported!
Muscle Muscle atrophy Nerve injurySilva-Couto2012Rev Bras FisioterEffects of low-level laser therapy after nerve reconstruction in rat denervated soleus muscle adaptation.RatLLLT applied to the nerve post-reconstruction was ineffective in delaying degenerative changes to the slow-twitch denervated muscles and in functional recovery in rats.
Wound healing Surgical wounds Ojea2016Photomed Laser SurgBeneficial Effects of Applying Low-Level Laser Therapy to Surgical Wounds After Bariatric Surgery.Human RCT/SBLLLT applied with the described protocol led to a decrease by biochemical markers and wound temperature compared with the placebo, which indicated that LLLT was able to control the inflammatory process; in addition, seroma and pain were reduced and cicatrization was improved by this preventive procedure.
Heart Heart failure Hentschke2016 epubLasers Med SciMaximal oxygen uptake and exercise tolerance are improved in rats with heart failure subjected to low-level laser therapy associated with resistance training.RatLLLT associated with [resistance training] improved oxygen uptake and exercise tolerance compared with [resistance training] alone in [heart failure] rats.
Tendons Achilles tendon Tenotomy + diabetesNouruzian2013Lasers Med SciEffect of low-level laser therapy on healing of tenotomized Achilles tendon in streptozotocin-induced diabetic rats.RatLLLT at 2.9 J/cm(2) to the tenotomized Achilles tendons in the non-diabetic and diabetic rats significantly increased the strength and maximum stress of repairing Achilles tendons in our study.
Respiratory system Lung inflammation Lung injury by ovalbumin+antibody LLLT vs chlorpromazine Biphasic dose responseAimbire2006Photomed Laser SurgLow-level laser therapy induces dose-dependent reduction of TNFalpha levels in acute inflammation.RatLLLT at a dose of 0.11 Joules reduced the TNF concentration in bronchoalveolar lavage fluid to 50.2 (95% CI, 49.4–51.0), which was significantly lower (p < 0.001) than the control group and the other LLLT groups of 0.04 and 0.22 Joules, respectively.
Respiratory system Lung hemorrhage Hemorrhage LLLT vs celecoxib vs dexamethasoneAimbire2007Photomed Laser SurgEffect of low-level laser therapy on hemorrhagic lesions induced by immune complex in rat lungs.RatLLLT at a dose of 2.6 Joules/cm(2) induces a reduction of HI (hemorrhagic index) levels and MPO activity in hemorrhagic injury that is not significantly different from celecoxib. Dexamethasone is slightly more effective than LLLT in reducing HI, but not MPO activity.
Respiratory system Lung inflammation Acute lung inflammationAimbire2008InflammationLow level laser therapy (LLLT) decreases pulmonary microvascular leakage, neutrophil influx and IL-1beta levels in airway and lung from rat subjected to LPS-induced inflammation.RatLLLT attenuated lung permeability. In addition, there was reduced neutrophil influx, myeloperoxidase activity and both IL-1beta in BAL and IL-1beta mRNA expression in trachea obtained from animals subjected to LPS-induced inflammation.
Immunity Macrophages (alveolar) de Lima2010Photomed Laser SurgLow-level laser therapy associated to N-acetylcysteine lowers macrophage inflammatory protein-2 (MIP-2) mRNA expression and generation of intracellular reactive oxygen species in alveolar macrophages.In vitroLLLT attenuated the MIP-2 mRNA expression and intracellular ROS generation after LPS or H(2)O(2). When the AM were pretreated with NAC, the laser effect was potentiated. BMS 205820 suppresses the effect of LLLT on MIP-2 mRNA expression and ROS generation, stimulated by LPS or H(2)O(2). On NF-κB transcription factor, both the LLLT and NAC reduced this protein in the AM exposed to LPS or H(2)O(2). The synergistic effect between LLLT and NAC on the reduction the NF-κB was also evidenced.
Tendons Achilles tendon Fillipin2005Lasers Surg MedLow-level laser therapy (LLLT) prevents oxidative stress and reduces fibrosis in rat traumatized Achilles tendon.RatLLLT by Ga-As laser reduces histological abnormalities, collagen concentration, and oxidative stress in an experimental model of Achilles tendon injury. Reduction of fibrosis could be mediated by the beneficial effects on the oxidant/antioxidant balance.
Stem cells & regeneration Fallahnezhad2016J Biomed OptLow-level laser therapy with helium-neon laser improved viability of osteoporotic bone marrow-derived mesenchymal stem cells from ovariectomy-induced osteoporotic rats.In vitroLLLT can enhance the viability and proliferation rate of healthy and especially osteoporotic autologous BMMSCs that could be very useful in regenerative medicine for the treatment of OP and fracture of patients who are OP-dependent
Bone Bone repair Bone graftBosco2016J Photochem Photobiol BEffects of low-level laser therapy on bone healing of critical-size defects treated with bovine bone graft.RatLLLT can improve bone formation process in CSD filled or not with BBG in rat calvaria, but it is not able to accelerate particles resorption of this material in the interior of bone defect.
Muscle Muscle injury Mesquita-Ferrari2011Lasers Med SciEffects of low-level laser therapy on expression of TNF-α and TGF-β in skeletal muscle during the repair process.RatLLLT caused a decrease in TNF-α mRNA expression at 1 and 7 days following injury and in TGF-β mRNA expression at 7 days following cryoinjury in comparison to the control group.
Muscle Myopathy Experimental myopathyServetto2010Lasers Surg MedEvaluation of inflammatory biomarkers associated with oxidative stress and histological assessment of low-level laser therapy in experimental myopathy.RatLLLT caused significant changes in inflammatory biomarkers and oxidative stress: decreased levels of fibrinogen, L-citrulline and SOD as opposed to the increase of NO in rats with experimental myopathies and significant muscle recovery. Comment: Parameters were reported incompletely. Laser spot size wasnt reported. However, results are interesting.
Muscle Muscle injury Lakyová2010Lasers Surg MedLow-level laser therapy for protection against skeletal muscle damage after ischemia-reperfusion injury in rat hindlimbs.RatLLLT confers a protective effect against early inflammatory tissue response, further atrophy, and necrosis of the muscle and it stimulates neovascularization after I/R injury.
Respiratory system Allergic asthma LLLT vs budesonideWang2014Lasers Med SciEffect of low-level laser therapy on allergic asthma in rats.RatLLLT could reduce levels of IL-4 and increase IFN-γ levels in bronchoalveolar lavage fluid and serum, meanwhile reduce serum IgE levels. Flow cytometry assay showed that LLLT can regulate the Th1/Th2 imbalance of asthmatic rats. LLLT had a similar effect to that of budesonide. These findings suggest that the mechanism of LLLT treatment of asthma is by adjustment of Th1/Th2 imbalance. Thus, LLLT could take over some of the effects of budesonide for the treatment of asthma, thereby reducing some of the side effects of budesonide.
Tendons Achilles tendon Tendon injuryde Jesus2015Lasers Med SciLow-level laser therapy in IL-1β, COX-2, and PGE2 modulation in partially injured Achilles tendon.RatLLLT decreased Achilles tendons inflammatory process.
Oral Oral mucositis Gautam2012Radiother OncolLow level laser therapy for concurrent chemoradiotherapy induced oral mucositis in head and neck cancer patients - a triple blinded randomized controlled trial.Human RCT/DBLLLT decreased the incidence of CCRT induced severe OM and its associated pain, dysphagia and opioid analgesics use.
Oral Oral mucositis Elderly patients Head&neck cancerGautam2015J Photochem Photobiol BLow level laser therapy against radiation induced oral mucositis in elderly head and neck cancer patients-a randomized placebo controlled trial.Human RCTLLLT decreased the severity of OM and oral pain in elderly HNC patients. Also, lesser weight loss, morphine analgesic use and radiation break happened in laser group.
Muscle Exercise Blood lipids, cholesterolAquino2013Lasers Med SciLow-level laser therapy (LLLT) combined with swimming training improved the lipid profile in rats fed with high-fat diet.RatLLLT decreased the total cholesterol (p < 0.05), triglycerides (p < 0.01), low-density lipoprotein cholesterol (p < 0.05), and relative mass of fat tissue (p < 0.05), suggesting increased metabolic activity and altered lipid pathways. The combination of exercise and LLLT increased the benefits of exercise alone. However, LLLT without exercise tended to increase body weight and fat content.
Circulation Arterial restenosis Derkacz2014Photomed Laser SurgEffects of intravascular low-level laser therapy during coronary intervention on selected growth factors levels.Human RCTLLLT decreases levels of TGF-β1 and FGF-2 in patients undergoing coronary intervention, which may explain smaller neointima formation. Note: This study seems to be based on the same patients as in the two other Derkacz et al. studies.
Muscle Muscle fatigue Gorgey2008Photomed Laser SurgThe effect of low-level laser therapy on electrically induced muscle fatigue: a pilot study.Human RCT CrossoverLLLT did not attenuate muscle fatigue evoked by NMES, but this needs to be further addressed in human studies and clinical settings. The lack of significant findings could be explained by the small sample size and the selection of LLLT parameters.
Skin Rejuvenation Pereira2016J Cosmet Laser TherNon-ablative radiofrequency associated or not with Low Level Laser Therapy on the treatment of facial wrinkles in adult women: a randomized single-blind clinical trial.Human RCT/SBLLLT did not potentiate RF treatment.
Oncology Tumor cells Barasch2016Support Care CancerEffects of pre-radiation exposure to LLLT of normal and malignant cells.In vitroLLLT does not confer protection and may even sensitize cancer cells to IR killing
Nerves Cranial Buchaim2016Lasers Med SciThe new heterologous fibrin sealant in combination with low-level laser therapy (LLLT) in the repair of the buccal branch of the facial nerve.RatLLLT exhibited satisfactory results on facial nerve regeneration, being therefore a useful technique to stimulate axonal regeneration process.
Pain Neck Konstantinovic2010Pain MedLow-level laser therapy for acute neck pain with radiculopathy: a double-blind placebo-controlled randomized study.Human RCT/DBLLLT gave more effective short-term relief of arm pain and increased range of neck extension in patients with acute neck pain with radiculopathy in comparison to the placebo procedure.
Muscle Exercise de Brito Vieira2014Photomed Laser SurgUse of low-level laser therapy (808 nm) to muscle fatigue resistance: a randomized double-blind crossover trial.Human RCT/DB CrossoverLLLT group increased RM (52%; p=0.002) with a small EFI for the vastus medialis (p=0.004) and rectus femoris (p=0.004).
Muscle Muscle injury Muscle injury DiabetesTakhtfooladi2016Lasers Med SciEvaluation of low-level laser therapy on skeletal muscle ischemia-reperfusion in streptozotocin-induced diabetic rats by assaying biochemical markers and histological changes.RatLLLT has a beneficial effect on the IR muscle injury treatment in the diabetic rats
Wound healing Wounds de Medeiros2016Lasers Med SciEffect of low-level laser therapy on angiogenesis and matrix metalloproteinase-2 immunoexpression in wound repair.RatLLLT improves wound healing by enhancing neocollagenesis, increasing the amount of new vessels formed in the tissue (neoangiogenesis), and modulating MMP-2 expression.
Tendons Achilles tendon Collagenase-induced tendinitisPires2011Lasers Med SciLow-level laser therapy (LLLT; 780 nm) acts differently on mRNA expression of anti- and pro-inflammatory mediators in an experimental model of collagenase-induced tendinitis in rat.RatLLLT in both acute and chronic phases decreased IL-6, COX-2, and TGF-β expression after tendinitis, respectively, when compared to tendinitis groups: IL-6, COX-2, and TGF-β. The LLLT not altered IL-1β expression in any time, but reduced the TNF-α expression; however, only at chronic phase. We conclude that LLLT administered with this protocol reduces one of features of tendinopathies that is mRNA expression for pro-inflammatory mediators.
Circulation Nitric oxide MIRE treatment with Anodyne LED pad deviceMitchell & Mack2013Am J Phys Med RehabilLow-level laser treatment with near-infrared light increases venous nitric oxide levels acutely: a single-blind, randomized clinical trial of efficacy.Human RCT/SBLLLT increased NO levels in venous blood draining from the treatment site in healthy subjects. The peak increase in NO occurred 5 mins into the treatment, after which it slowly waned. Further research is necessary to assess NO increases with LLLT in patients with pathologies.
Muscle Exercise Leal Junior2009Lasers Med SciEffect of 830 nm low-level laser therapy applied before high-intensity exercises on skeletal muscle recovery in athletes.Human RCT/DB CrossoverLLLT irradiation before the Wingate test seemed to inhibit an expected post-exercise increase in CK level and to accelerate post-exercise lactate removal without affecting test performance.
Pain Myofascial Hsieh2015Lasers Med SciFluence-dependent effects of low-level laser therapy in myofascial trigger spots on modulation of biochemicals associated with pain in a rabbit model.RabbitLLLT irradiation with fluences of 4.5 and 27 J/cm(2) at [myofascial trigger points] can significantly reduce SP level in [dorsal root ganglion]. LLLT with lower fluence of 4.5 J/cm(2) exerted lower levels of TNF-α and COX-2 expression in laser-treated muscle, but LLLT with higher fluence of 27 J/cm(2) elevated the levels of [β-endorphin] in serum, [dorsal root ganglion], and muscle.
Spinal column Hwang2015Photochem PhotobiolLow level light therapy modulates inflammatory mediators secreted by human annulus fibrosus cells during intervertebral disc degeneration in vitro.LLLT markedly inhibited secretion of IL-6 at 405 nm in a time-dependent manner. Level of IL-8 was significantly decreased at all wavelengths in a time-dependent manner.
Tendons Achilles tendon Salate2005Photomed Laser SurgEffect of In-Ga-Al-P diode laser irradiation on angiogenesis in partial ruptures of Achilles tendon in rats.RatLLLT of different intensities seems to promote neovascularization in damaged Achilles tendons of rats after partial rupture compared to controls.
Dermatology Herpes labialis Muñoz Sanchez2012Photomed Laser SurgThe effect of 670-nm low laser therapy on herpes simplex type 1.HumanLLLT of herpes simples virus 1 (HSV-1) appears to be an effective treatment modality without any observed side effects.
Hair Androgenetic alopecia TOPHAT655 deviceLanzafame2013Lasers Surg MedThe growth of human scalp hair mediated by visible red light laser and LED sources in males.Human (♂) RCT/DB LLLT of the scalp at 655 nm significantly improved hair counts in males with androgenetic alopecia.
Hair Androgenetic alopecia TOPHAT655 deviceLanzafame2014Lasers Surg MedThe growth of human scalp hair in females using visible red light laser and LED sources.Human (♀) RCT/DBLLLT of the scalp at 655 nm significantly improved hair counts in women with androgenetic alopecia at a rate similar to that observed in males using the same parameters.
Pain Analgesia Endogenous opioids Systemic effectsHagiwara2007Lasers Surg MedGaAlAs (830 nm) low-level laser enhances peripheral endogenous opioid analgesia in rats.RatLLLT produced an analgesic effect in inflamed peripheral tissue which was transiently antagonized by naloxone. Beta-endorphin precursor mRNA expression increased with LLLT, both in vivo and in vitro.
Cells Nitric oxide Macrophages Cell viabilitySilva2016Lasers Med SciIncrease in the nitric oxide release without changes in cell viability of macrophages after laser therapy with 660 and 808 nm lasers.In vitroLLLT promoted statistically significant changes in NO release and MTT value only at the wavelength of 660 nm (p < 0.05). LLLT also promoted an increase in the NO release and cell viability when the energy densities 64 (p = 0.04) and 214 J/cm2 (p = 0.012), respectively, were used.
Fibromyalgia Ruaro2014Lasers Med SciLow-level laser therapy to treat fibromyalgia.Human RCTLLLT provided relief from fibromyalgia symptoms in patients and should be further investigated as a therapeutic tool for management in fibromyalgia.
Muscle Muscle injury Assis2012Lasers Surg MedLow-level laser therapy (808 nm) reduces inflammatory response and oxidative stress in rat tibialis anterior muscle after cryolesion.RatLLLT reduced oxidative and nitrative stress in injured muscle, decreased lipid peroxidation, nitrotyrosine formation and NO production, probably due to reduction in iNOS protein expression. Moreover, LLLT increased SOD gene expression, and decreased the inflammatory response as measured by gene expression of NF-kβ and COX-2 and by TNF-α and IL-1β concentration.
Pain Allodynia Hsieh2016Support Care CancerLow-level laser therapy alleviates mechanical and cold allodynia induced by oxaliplatin administration in rats.RatLLLT relieved both cold and mechanical allodynia induced by oxaliplatin in rats. Oxaliplatin-related increases in protein levels of NGF and TRPM8 in DRG and SP in the dorsal horn were also reduced after LLLT. The findings of this study support LLLT as a potential treatment for oxaliplatin-induced neuropathy. Moreover, our findings suggest that SP, TRPM8, and NGF proteins in the superficial dorsal horn and DRG may be involved in an antiallodynic effect for LLLT.
Hair Androgenetic alopecia HairMax Laser Comb(®)Munck2014Int J TrichologyUse of low-level laser therapy as monotherapy or concomitant therapy for male and female androgenetic alopecia.Human Retrospective dataLLLT represents a potentially effective treatment for both male and female AGA, either as monotherapy or concomitant therapy.
Muscle Muscle injury PBM vs diclofenacde Paiva Carvalho2013Photochem PhotobiolEffects of low-level laser therapy (LLLT) and diclofenac (topical and intramuscular) as single and combined therapy in experimental model of controlled muscle strain in rats.RatLLLT showed better effects than TD and ID regarding PGE2 levels and walking track analysis (P < 0.05). We can conclude that LLLT has more efficacy than topical and intramuscular diclofenac in treatment of muscle strain injury in acute stage.
Heart Heart failure Heart failureHentschke2013Lasers Med SciLow-level laser therapy improves the inflammatory profile of rats with heart failure.RatLLLT showed systemic and skeletal muscle anti-inflammatory effects in rats with HF.
Tendons Achilles tendon Surgical tenotomyAliodoust2014Lasers Med SciEvaluating the effect of low-level laser therapy on healing of tentomized Achilles tendon in streptozotocin-induced diabetic rats by light microscopical and gene expression examinations.RatLLLT significantly decreased inflammation in diabetic rats on days 5 (p = 0.03) and 10 (p = 0.02) compared to the corresponding control diabetic rats. According to the students t test, LLLT significantly increased TGF-β1 gene expression in healthy (p = 0.000) and diabetic (p = 0.000) rats compared to their relevant controls. The He-Ne laser was effective in altering the inflammatory reaction and increasing TGF-β1 gene production.
Respiratory system Allergic rhinitis Biphasic dose responseChoi2013Evid Based Complement Alternat MedEffects of low level laser therapy on ovalbumin-induced mouse model of allergic rhinitis.MouseLLLT significantly inhibited total IgE, IL-4, and TARC expression in ovalbumin-induced mice at low dose irradiation. The protein expression level of IL-4 in spleen was inhibited in low dose irradiation significantly. IL-4 expression in EL-4 cells was inhibited in a dose dependent manner. Histological damages of the epithelium in the nasal septum were improved by laser irradiation with marked improvement at low dose irradiation. These results suggest that LLLT might serve as a new therapeutic tool in the treatment of AR with more effectiveness at low dose irradiation. To determine the optimal dose of laser irradiation and action mechanisms of laser therapy, further studies will be needed.
Oncology Tumor cells Sperandio2013J BiophotonicsLow-level laser therapy can produce increased aggressiveness of dysplastic and oral cancer cell lines by modulation of Akt/mTOR signaling pathway.In vitroLLLT significantly modified the expression of proteins related to progression and invasion in all the cell lines, and could aggravate oral cancer cellular behavior, increasing the expression of pAkt, pS6 and Cyclin D1 proteins and producing an aggressive Hsp90 isoform.
Brain Stroke Lee2016Restor Neurol NeurosciPre-conditioning with transcranial low-level light therapy reduces neuroinflammation and protects blood-brain barrier after focal cerebral ischemia in mice.MouseLLLT significantly reduced infarct size and edema and improved neurological and motor function 24 h after ischemic injury. In addition, LLLT markedly inhibited Iba-1- and GFAP-positive cells, which was accompanied by a reduction in the expression of inflammatory mediators and inhibition of MAPK activation and NF-κB translocation in the ischemic cortex. Concomitantly, LLLT significantly attenuated leukocyte accumulation and infiltration into the infarct perifocal region. LLLT also prevented BBB disruption after ischemic events, as indicated by a reduction of Evans blue leakage and water content. These findings were corroborated by immunofluorescence staining of the tight junction-related proteins in the ischemic cortex in response to LLLT.
Toxins Snake venom MyonecrosisBarbosa2009Photomed Laser SurgEffect of low-level laser therapy in the myonecrosis induced by Bothrops jararacussu snake venom.MouseLLLT significantly reduced myonecrosis by 83.5% at 24 h (p < 0.05) but not at 3 h, and AV therapy alone was ineffective for reducing myonecrosis at 3 and 24 h.
Joints Osteoarthritis (of hand) Baltzer2016Lasers Surg MedPositive effects of low level laser therapy (LLLT) on Bouchards and Heberdens osteoarthritis.HumanLLLT significantly reduced pain and ring size and increased range of motion after five and seven treatments (all Ps < 0.001). The effects were very large (all η(2) s > 0.14). No further significant change occurred between 7 and 10 treatments. The effects achieved after seven sessions persisted for 8 weeks. LLLT is a safe, non-invasive, efficient and efficacious means to reduce pain and swelling and to increase joint mobility in patients suffering from Heberdens and Bourchards OA.
Respiratory system Lung inflammation Oliveira2014J Photochem Photobiol BLow level laser therapy reduces acute lung inflammation in a model of pulmonary and extrapulmonary LPS-induced ARDS.MouseLLLT significantly reduced pulmonary and extrapulmonary inflammation in LPS-induced ARDS, as demonstrated by reduced number of total cells (p<0.001) and neutrophils (p<0.001) in BAL, reduced levels of IL-1beta, IL-6, KC and TNF-alpha in BAL fluid and in serum (p<0.001), as well as the number of neutrophils in lung parenchyma (p<0.001). LLLT is effective to reduce pulmonary inflammation in both pulmonary and extrapulmonary model of LPS-induced ARDS.
Muscle Muscle injury CryolesionAssis2013Lasers Med SciLow-level laser therapy (808 nm) contributes to muscle regeneration and prevents fibrosis in rat tibialis anterior muscle after cryolesion.RatLLLT significantly reduced the lesion percentage area in the injured muscle (p<0.05), increased mRNA levels of the transcription factors MyoD and myogenin (p<0.01) and the pro-angiogenic vascular endothelial growth factor (p<0.01). Moreover, LLLT decreased the expression of the profibrotic transforming growth factor TGF-β mRNA (p<0.01) and reduced type I collagen deposition (p<0.01). These results suggest that LLLT could be an effective therapeutic approach for promoting skeletal muscle regeneration while preventing tissue fibrosis after muscle injury.
Tendons Achilles tendon Partial tendon injuryde Jesus2014Photomed Laser SurgLow-level laser therapy on tissue repair of partially injured achilles tendon in rats.RatLLLT stimulated collagen I proliferation, improving the injured Achilles tendons healing process.
Cells Signalling pathways El Makakey2017 epubBiochem Biophys Rep (?)Comparative study of the efficacy of Pulsed Electromagnetic Field and Low Level Laser Therapy on Mitogen-Activated Protein KinasesHumanLLLT stimulates only the ERK pathway in MAPKS activation pathways.
Wound healing Burns 3rd degree burnVasheghani2009Photomed Laser SurgLow-level laser therapy using 80-Hz pulsed infrared diode laser accelerates third-degree burn healing in rat.RatLLLT using an 80-Hz pulsed infrared diode laser accelerated third-degree burn healing in rat. [17.6 vs 19.6 days]
Edema Paw Inflammatory paw edema by carrageenan HyperalgesiaChagas2015Lasers Med SciExpression of mPGES-1 and IP mRNA is reduced by LLLT in both subplantar and brain tissues in the model of peripheral inflammation induced by carrageenan.RatLLLT was able to reduce both mPGES-1 and IP mRNA expression in subplantar and brain tissues.
Oral Oral mucositis Patients with head/neck cancer (chemoradiotherapy)Gautam2013Support Care CancerEffect of low-level laser therapy on patient reported measures of oral mucositis and quality of life in head and neck cancer patients receiving chemoradiotherapy--a randomized controlled trial.Human RCT/DBLLLT was effective in improving the patients subjective experience of OM and QOL in HNC patients receiving CRT.
Lymphedema Lau&Cheing2009Photomed Laser SurgManaging postmastectomy lymphedema with low-level laser therapy.Human RCT/SBLLLT was effective in the management of PML, and the effects were maintained to the 4 wk follow-up.
Oral Orthodontics PainAlmallah2016J Clin Diagn ResEvaluation of Low Level Laser Therapy on Pain Perception Following Orthodontic Elastomeric Separation: A Randomized Controlled Trial.Human RCTLLLT was successful in reducing post-separation pain when the experimental side was compared to the placebo side at all assessment times in each group (p<0.05). There were no statistically significant differences between single and double irradiation groups in terms of pain reduction (p>0.05).
Muscle Muscle injury Muscle trauma Inflammation Biphasic dose response PBM vs diclofenacde Almeida2014Lasers Med SciWhat is the best treatment to decrease pro-inflammatory cytokine release in acute skeletal muscle injury induced by trauma in rats: low-level laser therapy, diclofenac, or cryotherapy?RatLLLT with 1 J dose significantly decreased (p < 0.05) IL-1β, IL-6, and TNF-α levels compared to non-treated injured group as well as diclofenac and cryotherapy groups. For inflammation marker reduction, the 1J dose was the most efficient (a biphasic dose response)!
Muscle Muscle injury Muscle trauma Inflammation Biphasic dose response PBM vs diclofenacde Almeida2013Photochem PhotobiolLow-level laser therapy and sodium diclofenac in acute inflammatory response induced by skeletal muscle trauma: effects in muscle morphology and mRNA gene expression of inflammatory markers.RatLLLT with all doses improved morphological aspects of muscle tissue, showing better results than injury and diclofenac groups. All LLLT doses also decreased (P < 0.05) COX-2 compared to injury group at all time points, and to diclofenac group at 24 h after trauma. In addition, LLLT decreased (P < 0.05) TNF-α compared both to injury and diclofenac groups at all time points. LLLT mainly with dose of 9 J is better than topical application of diclofenac in acute inflammation after muscle trauma. For inflammation marker reduction, the 1J dose was the most efficient (a biphasic dose response)!
Respiratory system Pleurisy Pleurisy Biphasic dose responseBoschi2008Lasers Surg MedAnti-Inflammatory effects of low-level laser therapy (660 nm) in the early phase in carrageenan-induced pleurisy in rat.RatLLLT-660 nm induced an anti-inflammatory effect characterized by inhibition of either total or differential leukocyte influx, exudation, total protein, NO, IL-6, MCP-1, IL-10, and TNF-alpha, in a dose-dependent manner. Under these conditions, laser treatment with 2.1 J was more effective than 0.9 and 4.2 J.
Cells Protection U2OS human osteosarcoma cells Mechanisms ATP production Oxygen consumption Spitler2015J Biomed OptCombination of low level light therapy and nitrosyl-cobinamide accelerates wound healing.In vitroLLLT-enhanced wound healing proceeded through an electron transport chain-C-ox-dependent mechanism with a reduction of reactive oxygen species and increased adenosine triphosphate production. C-ox was validated as the primary photoacceptor by three observations: increased oxygen consumption, reduced wound healing in the presence of sodium azide, and disassociation of cyanide, a known C-ox ligand, following LLLT. We conclude that LLLT and NO-Cbi accelerate wound healing through two independent mechanisms, the electron transport chain-C-ox pathway and cGMP signaling, respectively, with both resulting in ERK1/2 activation.
Brain Stroke Leung2002Lasers Surg MedTreatment of experimentally induced transient cerebral ischemia with low energy laser inhibits nitric oxide synthase activity and up-regulates the expression of transforming growth factor-beta 1.RatLow energy laser could suppress the activity of NOS and up-regulate the expression of TGF-beta1 after stroke in rats.
Cells Fibrosis FibroblastsSassoli2016Lasers Surg MedLow intensity 635 nm diode laser irradiation inhibits fibroblast-myofibroblast transition reducing TRPC1 channel expression/activity: New perspectives for tissue fibrosis treatment.In vitroLow intensity irradiation with 635 ± 5 nm diode laser inhibited TGF-β1/Smad3-mediated fibroblast-myofibroblast transition and this effect involved the modulation of TRPC1 ion channels. These data contribute to support the potential anti-fibrotic effect of LLLT and may offer further informations for considering this therapy as a promising therapeutic tool for the treatment of tissue fibrosis.
Tendons Achilles tendon Oliveira2009Lasers Surg MedEffect of low level laser therapy (830 nm) with different therapy regimes on the process of tissue repair in partial lesion calcaneous tendon.RatLow intensity laser therapy was effective in the improvement of collagen fibers organization of the calcaneous tendon after undergoing a partial lesion.
Brain Stroke Hippocampal slicesIwase1996Lasers Surg MedLow power laser irradiation reduces ischemic damage in hippocampal slices in vitro.In vitroLow power laser irradiation has acute protective effects against ischemic damage in brain slices.
Pain Back pain (no control group)Gur2003Lasers Surg MedEfficacy of low power laser therapy and exercise on pain and functions in chronic low back pain.HumanLow power laser therapy seemed to be an effective method in reducing pain and functional disability in the therapy of chronic LBP.
Oral Aphthous stomatitis da Silva Marciano2012Photochem Photobiol SciLaser for treatment of aphthous ulcers on bacteria cultures and DNA.In vitroLow-intensity red laser at therapeutic fluences has an effect on the survival of E. coli endonuclease III deficient cells, induces bacterial filamentation in E. coli cultures and DNA lesions targeted by exonuclease III.
Bone Bone repair Pires-Oliveira2010Osteoporos IntLaser 904 nm action on bone repair in rats with osteoporosis.RatLow-level 904-nm laser (50 mJ/cm(2)) accelerated the repair process of osteopenic fractures, especially in the initial phase of bone regeneration.
Tendons Achilles tendon VascularizationFerreira2015Photomed Laser SurgAchilles Tendon Vascularization of Proximal, Medial, and Distal Portion Before and After Partial Lesion in Rats Treated with Phototherapy.RatLow-level laser therapy (LLLT) had no effect on the studied parameters.
Pain Neck Chow2006PainThe effect of 300 mW, 830 nm laser on chronic neck pain: a double-blind, randomized, placebo-controlled study.Human RCT/DBLow-level laser therapy (LLLT), at the parameters used in this study, was efficacious in providing pain relief for patients with chronic neck pain over a period of 3 months. Editorial notes: Although patients were randomly assigned to the laser group and placebo group, there was a substantial imbalance of baseline pain scores between the groups (i.e. a difference of 1.9 on a 10-points scale).
Oral Oral mucositis Dose responseCarvalho2011Oral OncolEvaluation of low-level laser therapy in the prevention and treatment of radiation-induced mucositis: a double-blind randomized study in head and neck cancer patients.Human RCT/DBLow-level laser therapy during radiotherapy was found to be effective in controlling the intensity of mucositis and pain.
Muscle Cachexia (burn) Martins2015Acta Cir BrasLow-level laser therapy modulates musculoskeletal loss in a skin burn model in rats.RatLow-level laser therapy had positive effects on gastrocnemius muscle, improving tissue muscle morphology, increasing cross sectional area and MyoD immunoexpression.
Tendons Achilles tendon Partial tendon ruptureNeves2011Photomed Laser SurgDifferent power settings of LLLT on the repair of the calcaneal tendon.RatLow-level laser therapy resulted in significantly greater amounts of type III collagen (output powers of 60 mW or more) and type I collagen (output power of 80 mW), however, no significant differences between groups were found in the realignment of collagen fibers.
Nerves PNS Chronic constructive injury (CCI) Allodynia InflammationHsieh2012J Comp NeurolLow-level laser therapy alleviates neuropathic pain and promotes function recovery in rats with chronic constriction injury: possible involvements in hypoxia-inducible factor 1α (HIF-1α).RatLow-level laser therapy significantly improved paw withdrawal threshold and the sciatic, tibial, and peroneal functional indices after CCI. The therapy also significantly reduced the overexpressions of HIF-1α, TNF-α, and IL-1β, and increased the amounts of VEGF, NGF, and S100 proteins. In conclusion, a low-level laser could modulate HIF-1α activity. Moreover, it may also be used as a novel and clinically applicable therapeutic approach for the improvement of tissue hypoxia/ischemia and inflammation in nerve entrapment neuropathy, as well as for the promotion of nerve regeneration. These findings might lead to a sufficient morphological and functional recovery of the peripheral nerve.
Cosmetic medicine Cellulite Green lightJackson2013Lasers Surg MedA double-blind, placebo-controlled randomized trial evaluating the ability of low-level laser therapy to improve the appearance of cellulite.Human RCT/DBLow-level laser therapy using green 532 nm diodes is safe and effective for improving the appearance of cellulite in the thighs and buttocks.
Bone Bone repair Suture expansionAltan2015Lasers Med SciThe effect of dosage on the efficiency of LLLT in new bone formation at the expanded suture in rats.RatLow-level laser therapy with both 5 and 6,300 J/cm(2) doses was found to be significantly effective, while the 20 J/cm(2) dose did not show a significant effect in increasing new bone formation. This finding reveals that the efficiency of the therapy is affected by the dosage. Note: There was increase in bone formation in the medium dose group as well, but it was a little bit less pronounced. The bone formation increase was clearly highest in the low dose group (87%) compared to medium (41%) and high (51%) dose groups.
Tendons Achilles tendon Stergioulas2008Am J Sports MedEffects of low-level laser therapy and eccentric exercises in the treatment of recreational athletes with chronic achilles tendinopathy.Human RCTLow-level laser therapy, with the parameters used in this study, accelerates clinical recovery from chronic Achilles tendinopathy when added to an EE regimen. For the LLLT group, the results at 4 weeks were similar to the placebo LLLT group results after 12 weeks.
Pain Sciatica Biphasic dose response (?)Bertolini2011Arq NeuropsiquiatrLow-level laser therapy, at 830 nm, for pain reduction in experimental model of rats with sciatica.RatLow-level laser was effective in reducing the painful condition.
Wound healing Burns 2nd degree burnTrajano2015Lasers Med SciLow-level red laser improves healing of second-degree burn when applied during proliferative phase.RatLow-level red laser exposure contributes to the process of tissue repair of second-degree burns, but the intervention during proliferative phase is crucial in the final outcome of the repair process.
Mechanisms Original research Wound healingArany2007Wound Repair RegenActivation of latent TGF-beta1 by low-power laser in vitro correlates with increased TGF-beta1 levels in laser-enhanced oral wound healing.RatLow-power laser irradiation is capable of activating the latent TGF-beta1 complex in vitro and its expression pattern in vivo suggests that TGF-beta play a central role in mediating the accelerated healing response.
Oral Safety Chan2014Laser TherLow-power pulsed Nd:YAG laser irradiation for pre-emptive anaesthesia: A morphological and histological study.HumanLow-power pulsed Nd:YAG laser dose, as used in the clinical trial to induce anaesthesia, does not cause morphological damage to the mineralized tooth structure. Both Laser and EMLA groups showed minor superficial pulpal change following cavity preparation which was not statistically significant. Laser and Control groups minus preparation had no pulpal changes.
Eyes Del Olmo-Aguado2016Acta OphthalmolRed light of the visual spectrum attenuates cell death in culture and retinal ganglion cell death in situ.RatLow, non-toxic levels of red light focussed on the retina for a short period of time are sufficient to attenuate an insult of raised IOP to the rat retina. Since mitochondrial dysfunctions are thought to play a major role in ganglion cell death in glaucoma, we propose the potential use of red light therapy for the treatment of the disease.
Wound healing Wounds Santos2010Photomed Laser SurgEffects of laser photobiomodulation on cutaneous wounds treated with mitomycin C: a histomorphometric and histological study in a rodent model.RatLPBM resulted in reduced inflammation and an increase in both fibroblast proliferation and collagen deposition.
Pain Analgesia PulsingPonnudurai1987Acupunct Electrother ResHypoalgesic effect of laser photobiostimulation shown by rat tail flick test.RatLPBS of 4 Hz produced hypoalgesia of rapid onset and short duration while the response to 60 Hz was delayed and lasted longer. LPBS of 200 Hz did not produce any hypoalgesia.
Oral Tooth extraction Wisdom toothMarković & Todorović2007Int J Oral Maxillofac Surg.Effectiveness of dexamethasone and low-power laser in minimizing oedema after third molar surgery: a clinical trial.HumanLPL irradiation with local use of dexamethasone (group 2) resulted in a statistically significant reduction of postoperative oedema in comparison to the other groups. No adverse effects of the procedure or medication were observed. Comment: A good photograph of the LLLT treatment was supplied. Comment: Parameters were quite poorly reported.
Brain Alzheimers Disease Zhang2012Cell SignalInhibition of Aβ(25-35)-induced cell apoptosis by low-power-laser-irradiation (LPLI) through promoting Akt-dependent YAP cytoplasmic translocation.In vitro PC12 cellsLPLI inhibits Aβ25–35-induced apoptosis through Akt/YAP/p73 pathway.
Diabetes mellitus Glycemia Irradiation of salivary glandsFukuoka2016J BiophotonicsLow-power laser irradiation in salivary glands reduces glycemia in streptozotocin-induced diabetic female rats.RatLPLI probably reduced the hyperglycemia in diabetes by improving the insulin resistance in these animals Comment: A surprising results. I think it should be repeated.
Oral Periodontium Inflammation LED phototherapyChoi2012Lasers Med SciInflammatory cytokines are suppressed by light-emitting diode irradiation of P. gingivalis LPS-treated human gingival fibroblasts: inflammatory cytokine changes by LED irradiation.In vitroLPS treatment of gingival fibroblasts led to the increased release of the pro-inflammatory-related cytokines interleukin-6 (IL-6) and IL-8, whereas LED irradiation inhibited their release. Analysis of MAPK signal transduction revealed a considerable decrease in p38 phosphorylation in response to 635-nm radiation either in the presence or absence of LPS. In addition, 635-nm LED irradiation significantly promoted JNK phosphorylation in the presence of LPS. LED irradiation can inhibit activation of pro-inflammatory cytokines, mediate the MAPK signaling pathway, and may be clinically useful as an anti-inflammatory tool.
Immunity Lymphocytes Whole blood irradiationStadler2000Lasers Surg MedIn vitro effects of low-level laser irradiation at 660 nm on peripheral blood lymphocytes.In vitroLymphocyte proliferation was significantly higher (P<0.05) as expressed by a Stimulation Index in samples irradiated in the presence of whole blood compared with lymphocytes irradiated after isolation from whole blood. Free radical and lipid peroxide production also increased significantly when samples were irradiated in the presence of red blood cells. The present study supports the hypothesis that one mechanism for the photobiostimulation effect after irradiation at 660 nm is the reaction of light with hemoglobin, resulting in oxygen radical production.
Heart Coronary arteries Plass2012Lasers Surg MedLow-level-laser irradiation induces photorelaxation in coronary arteries and overcomes vasospasm of internal thoracic arteries.In vitroMacroscopic healthy LAD exposed to [low-level laser irradiation] revealed significant photorelaxation. With the administration of [low-level laser irradiation, 73% of the maximal obtainable effect by an endothelium-dependent vasodilator could be reached. Furthermore, [low-level laser irradiation] has the potential to overcome vasospasms of [internal thoracic arteries.
Oral Endodontics Liang2016Lasers Med SciPulpal response following photo-biomodulation with a 904-nm diode laser: a double-blind clinical study.Human RCT/DBMajority of the participants (66.7 %) demonstrated an analgesic effect following PBMT (elevated EPT scores); however, nine participants (30 %) reported the lower EPT scores than the control. Both the treatment effects (stimulation and analgesia) were significant compared to the placebo. In most individuals, PBMT of healthy teeth with a 904-nm GaAs diode laser can induce analgesia, as witnessed by elevated EPT scores. A converse effect can occur in a minority of subjects.
Oral Aphthous stomatitis CO2 laserPrasad & Pai2013Oral Surg Oral Med Oral Pathol Oral RadiolAssessment of immediate pain relief with laser treatment in recurrent aphthous stomatitis.Human RCTMean pain scores in the laser group were significantly reduced immediately after treatment (0.68 ± 0.6) compared with pretreatment (8.48 ± 0.71; P < .001). In contrast, the placebo group showed little difference in pain scores between pretreatment (8.08 ± 0.70) and immediately after treatment (7.96 ± 0.84). In the laser group, significant improvements in healing times were observed (4.08 ± 0.81 vs. 7.84 ± 0.90 days; P < .001). Comment: Interesting results with 10600nm CO2-laser! This cannot be explained by cytochrome oxidase, because wavelength is too long.
Brain Parkinsons disease MPTP LED phototherapy vs laser phototherapy Light delivery into the brain via optical fiberMoro2014J NeurosurgPhotobiomodulation inside the brain: a novel method of applying near-infrared light intracranially and its impact on dopaminergic cell survival in MPTP-treated mice.MouseMeasurements showed that the NIr intensity declined as distance from the source increased across the brain (65% per mm) but was detectable up to 10 mm away. At neuroprotective (0.16 mW) and much higher (67 mW) intensities, the NIr caused no observable behavioral deficits, nor was there evidence of tissue necrosis at the fiber tip, where radiation was most intense. Finally, the intracranially delivered NIr protected SNc cells against MPTP insult; there were consistently more dopaminergic cells in MPTP-treated mice irradiated with NIr than in those that were not irradiated. Comment: A really cool photograph is included!
Bone Bone repair Sella2015Lasers Med SciEffect of low-level laser therapy on bone repair: a randomized controlled experimental study.RatMicroscopic analysis revealed a significant decrease in inflammatory infiltration, intense trabecular bone matrix and periosteal formation, and an increase in newly formed bone after laser irradiation.
Oral Orthodontics Tooth movement Miniscrew stabilityEkizer2016Lasers Surg MedLight emitting diode mediated photobiomodulation therapy improves orthodontic tooth movement and miniscrew stability: A randomized controlled clinical trial.Human RCT/DB split-mouthMiniscrew stability was similar between control and LPT groups at baseline (T0) and the 1st month (T1). However, miniscrew stability was significantly increased in the LPT group in 2nd (T2) and 3rd (T3) months. Comparison of tooth movement during three different time intervals (T1-T0, T2-T1, and T3-T2) revealed that statistically significantly increased in every time intervals after LPT. No statistically significant change was detected in the IL-1β levels between groups. Comment: Parameters were poorly reported.
Wound healing Burns 2nd degree burnChiarotto2014Lasers Med SciEffects of laser irradiation (670-nm InGaP and 830-nm GaAlAs) on burn of second-degree in rats.RatMorphometric analysis showed that different lasers 670-nm InGaP and 830-nm GaAlAs reduced the number of granulocytes and an increase of newly formed vessels in radiated lesions. The 670-nm InGaP laser therapy was more effective in increasing the number of fibroblasts. The different treatments modified the expression of VEGF and TGF-β1, when compared with lesions not irradiated. The different types of light sources showed similar effects, improved the healing of second-degree burns and can help for treating this type of injury. Despite the large number of studies with LLTI application in second-degree burns, there is still divergence about the best irradiation parameters to be used.
Circulation Arterial restenosis Kipshidze2001CirculationEffect of short pulsed nonablative infrared laser irradiation on vascular cells in vitro and neointimal hyperplasia in a rabbit balloon injury model.RabbitMorphometry showed that the luminal area was significantly greater in the arteries subjected to laser treatment (1.92±0.21 mm2 in the treated arteries and 0.49±0.09 mm2 in the control animals, P=9.1×10−14) (Table). Similar significant differences were demonstrated in the neointimal areas (0.76±0.18 and 1.85±0.30 mm2 in laser and control arteries, respectively, P=2.2×10−11). The ratio EELinj/EELref was greater in laser than control vessels (1.41±0.08 versus 1.09±0.08, P=9.4×10−9). The present study also shows that endoluminal NIL has a significant effect on restenosis (Figures 5 and 6⇓; Table). When delivered endoluminally, NIL reduces neointimal hyperplasia in the rabbit injury model. This study, however, should not be regarded as definitive preclinical data, and further experiments in the porcine coronary model are necessary to further establish the efficacy of this therapy. Ultimately, these data may lead to the development of new methods for the prevention of restenosis.
Brain Alzheimers Disease 5XFAD transgenic mice Systemic effectsFarfara2015J Mol NeurosciLow-level laser therapy ameliorates disease progression in a mouse model of Alzheimers disease.MouseMSCs from wild-type mice stimulated with LLLT demonstrated an increased ability to maturate toward a monocyte lineage and to increase phagocytosis of soluble Aβ in vitro. Furthermore, weekly LLLT for 2 months to the BM, starting at 4 months of age (progressive stage of the disease in these 5XFAD transgenic male mice), improved memory and spatial learning, compared to a sham-treated AD mouse model. Histology revealed a significant reduction in Aβ brain burden in the laser-treated mice compared to the nonlaser-treated ones.
Brain Alzheimers Disease Systemic effectsOron2016Photomed Laser SurgLow-Level Laser Therapy to the Bone Marrow Ameliorates Neurodegenerative Disease Progression in a Mouse Model of Alzheimers Disease: A Minireview.MouseMSCs from wild-type mice stimulated with LLLT showed to increase their ability to maturate towards a monocyte lineage and to increase phagocytosis activity towards soluble amyloid beta (Aβ). Furthermore, weekly LLLT to BM of AD mice for 2 months, starting at 4 months of age (progressive stage of AD), improved cognitive capacity and spatial learning, as compared to sham-treated AD mice. Histology revealed a significant reduction in Aβ brain burden.
Oral Orthodontics Kau2013Prog OrthodPhotobiomodulation accelerates orthodontic alignment in the early phase of treatment.Human MulticenterMulti-level mixed effect regression analysis was performed on the data, and the mean rate of change in LII was 0.49 and 1.12 mm/week for the control and test groups, respectively.
Ligaments MCL injury Single vs multiple treatmentsNg2004Lasers Surg MedComparison of single and multiple applications of GaAlAs laser on rat medial collateral ligament repair.RatMultiple laser therapy improves the normalized strength and stiffness of repairing rat MCLs at 3 weeks after injury. The multiple treatments seem to be superior to a single treatment when the cumulative dosages are comparable between the two modes of application.
Wound healing Pressure ulcer LLLT cluster (46)Taly2004Arch Phys Med RehabilEfficacy of multiwavelength light therapy in the treatment of pressure ulcers in subjects with disorders of the spinal cord: A randomized double-blind controlled trial.Human RCT/DBMultiwavelength light therapy from a gallium-aluminum-arsenide laser source did not influence overall healing pressure ulcers. Limited evidence suggested that it improved healing of stage 3 and 4 pressure ulcers.
Muscle Muscle activity Vassão2016Lasers Med SciEffects of photobiomodulation on the fatigue level in elderly women: an isokinetic dynamometry evaluation.Human RCT/DBMuscle performance was evaluated using an isokinetic dynamometer. The results showed that photobiomodulation was able of reducing muscle fatigue by a significant increase of electromyographic fatigue index (EFI) (p = 0.047) and decreasing significantly lactate concentration 6 min after the performance of the fatigue protocol (p = 0. 0006) compared the placebo laser session. However, the photobiomodulation was not able of increasing muscle performance measured by the isokinetic dynamometer.
Eyes Age-related macular degenerationCalaza2015Neurobiol AgingMitochondrial decline precedes phenotype development in the complement factor H mouse model of retinal degeneration but can be corrected by near infrared light.MouseNear infrared (NIR) increases ATP and reduces inflammation. [...] In summary, we provide evidence for a mitochondrial basis for this disease in mice and correct this with simple light exposure known to improve mitochondrial function.
Nerves PNS LED phototherapyIshiguro2010J Orthop SciEffect of near-infrared light-emitting diodes on nerve regeneration.Nerve regeneration was promoted in the LED group. Antioxidation of the chamber fluid significantly decreased from 3 days to 7 days in the control group. In the LED group, antioxidation levels did not decrease until 7 days.
Bone Bone repair LED phototherapyEkizer2013Lasers Med SciLight-emitting diode photobiomodulation: effect on bone formation in orthopedically expanded suture in rats--early bone changes.RatNew bone formation area (p = 0.024, 1.48-fold), number of osteoblasts (p < 0.001, 1.59-fold), number of osteoclasts (p = 0.004, 1.43-fold), and number of vessels (p = 0.007, 1.67-fold) showed higher values in the experimental group than the control. Bone histomorphometric measurements revealed that bone architecture in the LPT group was improved.
Bone Bone repair Autogenous bone block graftde Almeida2016Arch Oral BiolInfluence of low-level laser therapy on the healing process of autogenous bone block grafts in the jaws of systemically nicotine-modified rats: A histomorphometric study.RatNicotine harms bone formation in the bed-graft interface and LLLT action can mitigate this.
Respiratory system Rhinosinusitis Krespi&Kizhner2011Lasers Surg MedPhototherapy for chronic rhinosinusitis.Human RandomizedNILI of the nasal sinuses with or without PA agents proved to be beneficial objectively and subjectively in CRS patients who failed medical and surgical therapies.
Wound healing Venous ulcer Gupta1998Dermatol SurgThe use of low energy photon therapy (LEPT) in venous leg ulcers: a double-blind, placebo-controlled study.Human RCT/DBNine patients with 12 venous ulcers were randomized to receive LEPT or placebo therapy. At the conclusion of the study, the percentage of the initial ulcer area remaining unhealed in the LEPT and placebo groups was 24.4% and 84.7%, respectively (P = 0.0008). The decrease in ulcer area (compared to baseline) observed in the LEPT and placebo groups was 193.0 mm2 and 14.7 mm2, respectively (P = 0.0002).
Heart MI Ischemia-reperfusion LED phototherapy LED clusterQuirk2014Photomed Laser SurgCardioprotection from ischemia-reperfusion injury by near-infrared light in rats.RatNIR application had no effect on the function of the nonischemic isolated heart, and had no effect on infarct size when applied during global ischemia. In the in vivo model, NIR commencing immediately before reperfusion decreased infarct size by 40%, 33%, 38%, and 77%, respectively, after regional ischemic periods of 30, 20, 15, and 10 min.
Mechanisms Original research Heger2010J Photochem Photobiol BAbsence of 633-nm laser irradiation-induced effects on glucose phosphorylation by hexokinase.In vitroNo differences in reaction rates between the NROF-irradiated and control groups were found at either temperature. Note: Amat published a critical comment to this paper.
Nerves Diabetic neuropathy LED phototherapy LED clusterSwislocki2010J Pain Symptom ManageA randomized clinical trial of the effectiveness of photon stimulation on pain, sensation, and quality of life in patients with diabetic peripheral neuropathy.Human RCTNo differences, over time, in any pain intensity scores (i.e., pain intensity immediately post-treatment, average pain, worst pain) or pain relief scores were found between the placebo and treatment groups. Four treatments with photon stimulation resulted in significant improvements in some pain qualities, sensation, and QOL outcomes in a sample of patients with a significant amount of pain and disability from their diabetes. A longer duration study is needed to further refine the photon stimulation treatment protocol in these chronically ill patients and to evaluate the sustainability of its effects. Comment: Parameters were quite shortly reported. These studies on diabetic neuropathy werent done by photobiomodulation researchers.
Nerves Diabetic neuropathy MIRE treatment with Anodyne LED pad deviceNawfar & Yacob2011Singapore Med JEffects of monochromatic infrared energy therapy on diabetic feet with peripheral sensory neuropathy: a randomised controlled trial.Human RCT/SBNo improvement of neuropathy was observed following MIRE treatment in the neuropathic feet of diabetic patients.
Bone Bone repair Atasoy2017Braz Oral ResThe efficacy of low-level 940 nm laser therapy with different energy intensities on bone healing.RatNo significant change was observed in the number of osteocytes, osteoblasts, osteoclasts and newly formed vessels at either time period across all laser groups. Although LLLT with the 10 J/cm2 energy density increased fibroblast activity at the 4th week in comparison with the 5 and 20 J/cm2 groups, no significant change was observed between the laser groups and the control group. These results indicate that low-level 940 nm laser with different energy intensities may not have marked effects on the bone healing process in both phases of bone formation.
Bone Bone repair Fekrazad2016Photomed Laser SurgEffects of Photobiomodulation and Mesenchymal Stem Cells on Articular Cartilage Defects in a Rabbit Model.RabbitNo significant difference in new cartilage formation and inflammation was found between the groups (p > 0.05). However, there was significantly more new bone formation in the experimental group (p < 0.05).
Oral Salivary glands Hypothyroid ratsde Jesus2015Lasers Med SciInfluence of laser photobiomodulation (GaAlAs) on salivary flow rate and histomorphometry of the submandibular glands of hypothyroid rats.RatNo significant difference was found in the salivary flow of rats that received laser photobiomodulation compared with their control groups. Histological analysis revealed a decrease in the parenchyma of the salivary glands of hypothyroid rats, but the laser was not able to reverse this process. Hypothyroid rats irradiated or not with laser showed acini and acinar cells with significantly smaller areas than euthyroid groups. The laser photobiomodulation protocol used was not able to change salivary flow or reverse the acinar atrophy process in the submandibular glands of hypothyroid rats.
Pain Back pain Ay2010Clin RheumatolIs low-level laser therapy effective in acute or chronic low back pain?Human RCT/DBno significant differences were detected between four treatment groups with respect to all outcome parameters (p > 0.05)
Wound healing Venous ulcer Franek2002Med Eng PhysDoes low output laser stimulation enhance the healing of crural ulceration? Some critical remarks.HumanNo significant impact of laser light (lambda=810 nm, P=65 mW, p=4 J/cm2) on any of the stages of ulceration healing was observed.
Penetration Thermal effects Grandinétti Vdos2015Lasers Med SciThe thermal impact of phototherapy with concurrent super-pulsed lasers and red and infrared LEDs on human skin.No significant skin temperature increases were observed among the different skin color groups (p > 0.05), age groups (p > 0.05), or gender groups (p > 0.05). Our results indicate that the concurrent use of super-pulsed lasers and pulsed red and infrared LEDs can be utilized in patients with all types of skin pigmentation without concern over safety or excessive tissue heating.
Tendons Achilles tendon MicrocirculationChang2015J Orthop Sports Phys TherEffects of Therapeutic Physical Agents on Achilles Tendon Microcirculation.HumanNo significant THb and StO2 differences were found after the application of interferential current or low-level laser.
Oral Orthodontics Altan2012Lasers Med SciMetrical and histological investigation of the effects of low-level laser therapy on orthodontic tooth movement.RatNo statistical difference was found for the amount of tooth movement in between the control and study groups (p > 0.05). The number of osteoclasts, osteoblasts, inflammatory cells, capillary vascularization, and new bone formation were found to be increased significantly in group II (p < 0.05). Immunohistochemical staining findings showed that RANKL immunoreactivity was stronger in group II than in the other groups. Group III (the lower-dose LLLT group) didnt seem to have any important benefits.
Muscle Exercise Biceps braquialisHigashi2013Photomed Laser SurgEffects of low-level laser therapy on biceps braquialis muscle fatigue in young women.Human RCT CrossoverNo statistical differences were found for eletromyographic fatigue and blood lactate values between groups. Mean numbers of elbow flexion-extension repetitions were 22.6 ± 7.58 after placebo, and 25.1 ± 9.89 after active LLLT group, but these differences were not statistically significant (p=0.342).
Lymphedema Comparison trialRidner2013Oncol Nurs ForumA pilot randomized trial evaluating low-level laser therapy as an alternative treatment to manual lymphatic drainage for breast cancer-related lymphedema.Human RCTNo statistically significant between-group differences were found in volume reduction; however, all groups had clinically and statistically significant reduction in volume. No group differences were noted in psychological and physical symptoms or QOL; however, treatment-related improvements were noted in symptom burden within all groups. Skin improvement was noted in each group that received LLLT. LLLT with bandaging may offer a time-saving therapeutic option to conventional MLD. Alternatively, compression bandaging alone could account for the demonstrated volume reduction. Lasers may provide effective, less burdensome treatment for lymphedema. Comment: Parameters were very poorly reported.
Nerves PNS Bagis2003Lasers Med SciNo effect of GA-AS (904 nm) laser irradiation on the intact skin of the injured rat sciatic nerve.RatNo statistically significant difference (p > 0.05) was found regarding the amplitude, area, duration and conduction velocity of CMAP for each applied dose (0.31, 2.48 and 19 J/cm2) on the irradiated (right) side and the control (left) side, or between irradiated groups. Twenty-one days after injury there were no qualitative differences in the morphological pattern of the regenerated nerve fibres in either irradiated (0.31, 2.48 and 19 J/cm2) or control nerves when evaluated by light microscopy. This study showed that low-energy GaAs irradiation did not have any effect on the injured rat sciatic nerve.
Oral Orofacial pain Hansen & Thorøe1990PainLow power laser biostimulation of chronic oro-facial pain. A double-blind placebo controlled cross-over study in 40 patients.Human Crossover/DBNo statistically significant difference between the analgesic effect of the laser and placebo irradiation was found on VAS-scales. Jan Tuner: It is interesting to note that the authors themselves state the origin of burning mouth as multifactor, psychosomatic or psychogenic. Thus, there would be no actual injury to the tissue, and laser, like any other modality, would have no effect. The negative 5-HIAA measurement in the laser group may indeed confirm the inappropriate inclusion parameters and laser energies in this study.
Hearing Hearing loss Goodman2013ISRN OtolaryngolThe effect of low-level laser therapy on hearing.Human RCT/DBNo statistically significant differences were found between groups for any of the auditory tests. Additionally, no clinically significant differences were found in any individual subjects. Comment: Parameters were poorly reported.
Oral TMJ Insufficient dosageLeal de Godoy2015J Oral Maxillofac SurgEffect of low-level laser therapy on adolescents with temporomandibular disorder: a blind randomized controlled pilot study.Human RCTNo statistically significant differences were found regarding pain, mandibular range of motion, or the distribution of occlusal contacts after treatment with low-level laser therapy. Tuner: The energy used here is 1 J per point (50 mW x 20 s = 1000 mJ = 1 J). For a muscle, this is far from the therapeutic window and a failure is to be expected. We found 6 J per point effective, but not necessarily optimal(Ahrari et al. 2013), even higher energies are sometimes clincally needed for reasonable results. Muscles are thick and contain a lot of hemoglobin, a major absorber of the light. Irradiation with or without pressure also changes to energy at target. The laser parameters here are well described but inadequate.
Oral Tooth extraction Wisdom toothRøynesdal1993Int J Oral Maxillofac SurgThe effect of soft-laser application on postoperative pain and swelling. A double-blind, crossover study.Human Crossover, DBNo statistically significant differences were observed in comparison of the experimental side with the placebo side.
Parameters Original research Giacci2015J Vis ExpMethod for the assessment of effects of a range of wavelengths and intensities of red/near-infrared light therapy on oxidative stress in vitro.In vitroNon-coherent Xenon light was filtered through narrow-band interference filters to deliver varying wavelengths (center wavelengths of 440, 550, 670 and 810 nm) and fluences (8.5x10(-3) to 3.8x10(-1) J/cm2) of light to cultured cells. While the fluences of R/NIR-LT used in the current study did not exert an effect on ROS generated by the cultured cells, the method of light delivery is applicable to other systems including isolated mitochondria or more physiologically relevant organotypic slice culture models, and could be used to assess effects on a range of outcome measures of oxidative metabolism.
Adipose tissue Inflammation LED phototherapyYoshimura2016J BiophotonicsPhotobiomodulation reduces abdominal adipose tissue inflammatory infiltrate of diet-induced obese and hyperglycemic mice.MouseNon-irradiated control animals display inflammatory areas almost five times greater than the treated group (p < 0.001). This result on inflammatory infiltrate may have caused impacts on the significant lower blood glucose level from irradiated animals (p = 0.04), twenty-four hours after the last irradiation session.
Hearing Tinnitus Hahn2008Int Tinnitus JMultimodal therapy for chronic tinnitus.HumanNone of the treatment modalities had an objective correlate of improvement, though improvement was reported by a visual analog scale.
Oral Oral mucositis Campos2009Photomed Laser SurgImprovement in quality of life of an oncological patient by laser phototherapy.Human Case reportNormal oral function and consequent improvements in the quality of life of this oncologic patient were observed with LPT.
Oral Wound healing: palatal wounds Keskiner2016Photomed Laser SurgEffect of Photobiomodulation on Transforming Growth Factor-β1, Platelet-Derived Growth Factor-BB, and Interleukin-8 Release in Palatal Wounds After Free Gingival Graft Harvesting: A Randomized Clinical Study.Human RCTObserved increases in PWF TGF-β1, PDGF-BB, and IL-8 levels suggest that PBM may accelerate wound healing by stimulating production of selected mediators.
Wound healing Venous ulcer Gupta1997J Dermatolog TreatThe use of low-energy photon therapy in the treatment of leg ulcers – a preliminary studyHuman Pilot studyOf 15 venous ulcers, 12 (75%) had healed or improved markedly (greater than 75% reduction in pretherapy area of ulcer) by the end of the study. Side-effects consisted of erythema at the ulcer site in one patient.
Skin Acne vulgaris Noborio2009Photodermatol Photoimmunol PhotomedClinical effect of low-energy double-pass 1450 nm laser treatment for acne in Asians.Human Open studyOf the 30 patients, 27 completed the study. The mean acne grades decreased from 3.9 to 1.4 (P<0.01) in the 27 patients. The pain was tolerated by 25 patients, and two patients required local anesthesia. No remarkable side effects occurred in any of the patients; all but a few patients had transient faint erythema.
Tendons de Quervains tenosynovitis Sharma2015Indian J OrthopOutcome of low level lasers versus ultrasonic therapy in de Quervains tenosynovitis.Human Comparison trialOn comparing both the groups, no statistically significant difference was found. However, looking at the mean values, the grip strength and VAS showed better improvement in the US Th. group as compared to the laser therapy group.
Ligaments MCL injury Dose responseDelbari2007Photomed Laser SurgEffect of low-level laser therapy on healing of medial collateral ligament injuries in rats: an ultrastructural study.RatOn day 12, the fibril dimension of group 2 and their density were higher than of groups 1 and 3. Although we could not find significant difference between density of fibrils of laser groups and other groups, the p value shows a difference almost at the range of significance (p = 0.059).
Muscle Muscle injury Diabetic ratsFrança2013Lasers Med SciEffect of laser therapy on skeletal muscle repair process in diabetic rats.RatOn day 14, the LLLT group was in the remodeling phase; the D group was still in the proliferative phase, with fibrosis, chronic inflammation, and granulation tissue; and the D-LLLT group was in an intermediary state in relation to the two previous groups. Under polarized light, on day 14, the LLLT and D-LLLT groups had organized collagen bundles in the perimysium, whereas the diabetic groups exhibited fibrosis.
Wound healing Wounds Li2016PLoS OneThe Histopathological Investigation of Red and Blue Light Emitting Diode on Treating Skin Wounds in Japanese Big-Ear White Rabbit.RabbitOn days 16 and 17 of irradiation, the healing rates in red (15 min and 30 min) and blue (15 min and 30 min) groups were 50%, 37.5%, 25% and 37.5%, respectively, while the healing rate in the control group was 12.5%. The percentage healed area in the red light groups was significantly higher than those in other groups. Collagen fiber and skin thickness were significantly increased in both red light groups; expression of EGF, FGF, CD31 and Ki67 in the red light groups was significantly higher than those in other groups; the expression of FGF in red (30 min) group was not significantly different from that in the blue light and control groups. The effect of blue light on wound healing was poorer than that of red light. Red light appeared to hasten wound healing by promoting fibrous tissue, epidermal and endothelial cell proliferation. An increase in the exposure time to 30 min did not confer any additional benefit in both red and blue light groups. This study provides a theoretical basis for the potential therapeutic application of LED light in clinical settings.
Wound healing Wounds Angiogenesis Biphasic dose response LED phototherapy LED vs LLLTCorazza2007Photomed Laser SurgPhotobiomodulation on the angiogenesis of skin wounds in rats using different light sources.RatOn days 3, 7, and 14, the proliferation of blood vessels in all irradiated groups was superior in comparison to those of the control group (p < 0.05). Treatment with fluence of 5 J/cm(2) was better than the laser group with 20 J/cm(2) on day 21. Red LLLT and LED demonstrated expressive results in angiogenesis. Light coherence was shown not to be essential to angiogenesis.
Poor science Malm1991Scand J Plast Reconstr Surg Hand SurgEffect of low power gallium arsenide laser on healing of venous ulcers.One group received standard conservative treatment and gallium arsenide laser, and the other received the same standard treatment and placebo laser treatment. There were no differences in results between the two groups. The parameters stated in the report are: A GaAs laser (Irradia) was used. The wavelength was 904 nm, average output 4 mW, peak power 10 W, pulse frequency 3800 Hz and duration 180 ns, and divergence 70 mrad. Energy density was 1.96 J/cm2 . The placebo laser was of the same brand but the invisible GaAs laser light had been removed so that nobody in the study could tell the difference between the two. According to Hode&Tuner: [Read additional info]
Brain Alzheimers Disease Cerebellar injuryPurushothuman2015Neurosci LettNear infrared light mitigates cerebellar pathology in transgenic mouse models of dementia.MouseOne month of NIr treatment mitigated the deposition of β-amyloid in cerebellar cortex of APP/PS1 mice, and the formation of neurofibrillary tangles, the hyperphosphorylation of tau, the damage caused by oxidative stress and the downregulation of cytochrome oxidase expression by Purkinje cells in the cerebellar cortex of K3 mice. These findings show the ability of NIr to mitigate degeneration in many - probably all - regions of the mouse brain.
Joints Osteoarthritis Gworys2012Ortop Traumatol RehabilInfluence of various laser therapy methods on knee joint pain and function in patients with knee osteoarthritis.Human RCTOne-wave laser irradiation at a dose of 8 J per point and two-wave laser irradiation with doses of 12.4 J and 6.6 J per point significantly improved knee joint function and relieved knee pain in patients with osteoarthritis.
Opioid withdrawal Morphine Mirzaii-Dizgah2009Behav Brain ResAttenuation of morphine withdrawal signs by low level laser therapy in rats.RatOne-way ANOVA showed that the LILT which applied immediately or 15min prior to naloxone injection significantly decreased total withdrawal score (TWS). These results suggest that LILT prior to naloxone injection attenuates the expression of withdrawal signs in morphine-dependent rats. Further studies may elucidate the likely role of LILT in clinical management of opioid withdrawal syndrome. Comment: The effect of LLLT was quite modest, but probably still relevant.
Oral Graft-versus-host disease Epstein2016Support Care CancerPhotobiomodulation therapy in the management of chronic oral graft-versus-host disease.Human Case seriesOral pain, sensitivity, and dry mouth improved in most patients. These findings suggest PBM therapy may represent an additional approach for management of oral cGVHD, and suggest that controlled studies should be conducted to confirm the efficacy and safety of PBM therapy in oral cGVHD and to determine optimal PBM therapy protocols.
Hearing Auditory neuropathy Ouabain-induced auditory neuropathyLee2016Neurosci LettPhotobiomodulation by laser therapy rescued auditory neuropathy induced by ouabain.GerbilOuabain application increased the ABR thresholds increase, while the use of ouabain plus laser produced lower threshold compared to the ouabain group. Hematoxylin and Eosin staining of cochlea mid-modiolar sections in animals treated with ouabain showed damaged spiral ganglion cells, neurofilaments, and post synaptic puncta. Ouabain plus laser group showed higher number of spiral ganglion cells, higher density of neurofilaments, and higher number post synaptic puncta counts compared with ouabain application group. Star: Parameters were well reported, and a good-quality photograph was supplied.
Muscle Energy metabolism Biphasic dose responseXu2008Photomed Laser SurgLow-intensity laser irradiation improves the mitochondrial dysfunction of C2C12 induced by electrical stimulation.In vitroOur data (as shown in Fig. 2) suggest that doses of 0.33–8.22 J/cm2 do no harm to the mitochondrial function of normal cells, while doses of 11.22–14.16 J/cm2 are beyond the point at which PBM is beneficial, and such doses can actually worsen cellular function (p  0.01), a finding consistent with that of the study done by Lavi et al. Our current research also showed that LIL irradiation at doses of 0.33–8.22 J/cm2 had a photobiomodulating effect on C2C12 myotubes, as manifested by the improvement of mitochondrial function compared with 75 min of electrical stimulation (p  0.01), and that LIL doses of 0.33 and 1.338 J/cm2 reversed the dysfunctional state induced by the electrical stimulation, as shown in Fig. 2.
Eyes Rutar2012J Neuroinflammation670-nm light treatment reduces complement propagation following retinal degeneration.RatOur data indicate that 670-nm light pretreatment reduces lipid peroxidation and complement propagation in the degenerating retina. These findings have relevance to the cellular events of complement activation underling the pathogenesis of AMD, and highlight the potential of 670-nm light as a non-invasive anti-inflammatory therapy.
Nerves Spinal cord Chronic compression of dorsal root ganglionChen2014PLoS OneEffect of low level laser therapy on chronic compression of the dorsal root ganglion.RatOur data indicate that LLLT significantly decreased the tolerable sensitivity to pain and heat stimuli in the CCD groups. The expression levels of the pro-inflammatory cytokines TNF-α and IL-1β were increased following CCD, and we found that these increases could be reduced by the application of LLLT. Furthermore, the expression of GAP-43 was enhanced by LLLT. In conclusion, LLLT was able to enhance neural regeneration in rats following CCD and improve rat ambulatory behavior. The therapeutic effects of LLLT on the DRG during CCD may be exerted through suppression of the inflammatory response and induction of neuronal repair genes. These results suggest potential clinical applications for LLLT in the treatment of compression-induced neuronal disorders.
Mechanisms Original research Bovine liver mitochondria Flat-top handpieceAmaroli2016Photomed Laser SurgAn 808-nm Diode Laser with a Flat-Top Handpiece Positively Photobiomodulates Mitochondria Activities.In vitroOur data show for the first time that even the higher fluences (64 J/cm2-1 W), similar to the low fluences, can photobiostimulate the mitochondria respiratory chain without uncoupling them and can induce an increment in the ATP production. These results suggest that the negative effects of higher fluences observed to date are not unequivocally due to higher fluence per se but might be a consequence of the irradiation carried by handpieces with a Gaussian profile.
Brain Alzheimers Disease Yang2010NeuroscienceLow energy laser light (632.8 nm) suppresses amyloid-β peptide-induced oxidative and inflammatory responses in astrocytes.In vitro Rat astrocytesOur data showed that laser light at 632.8 nm suppressed Aβ-induced superoxide production, colocalization between NADPH oxidase gp91(phox) and p47(phox) subunits, phosphorylation of cPLA(2,) and the expressions of IL-1β and iNOS in primary astrocytes. We demonstrated for the first time that 632.8 nm laser was capable of suppressing cellular pathways of oxidative stress and inflammatory responses critical in the pathogenesis in AD.
Brain Stroke Atherothrombotic stroke Transcranial LLLTOron (A)2006StrokeLow-level laser therapy applied transcranially to rats after induction of stroke significantly reduces long-term neurological deficits.RatOur data suggest that a noninvasive intervention of LLLT issued 24 hours after acute stroke may provide a significant functional benefit with an underlying mechanism possibly being induction of neurogenesis. Note: Application of the laser at 4 hours poststroke did not affect the neurological outcome of the stroke-induced rats as compared with controls.
Heart MI MIManchini2014PLoS OneAmelioration of cardiac function and activation of anti-inflammatory vasoactive peptides expression in the rat myocardium by low level laser therapy.RatOur data suggest that LLLT diminishes the acute inflammation in the myocardium, reduces infarct size and attenuates left ventricle dysfunction post-MI and increases vasoactive peptides expression and nitric oxide (NO) generation.
Bone Bone repair Alendronate potentiationAkyol2015Lasers Med SciThe influence of low-level laser therapy with alendronate irrigation on healing of bone defects in rats.RatOur findings demonstrated that Aln has a more positive effect with LLLT on bone healing in rats. It was concluded that combining LLLT with Aln irrigation has a beneficial effect in bone repair. It was demonstrated experimentally that Aln irrigation during the surgery had a significant effect to enhance bone formation, and LLLT significantly potentiated the osseous healing effects of Aln on bone defects. This administration method is able to minimize the dose of Aln in order to avoid both systemic and local adverse effects as well as the local injection times during the bone healing process.
Brain Parkinsons disease MPTPDarlot2016Ann NeurolNear-infrared light is neuroprotective in a monkey model of Parkinson disease.MonkeyOur findings indicate NIr to be an effective therapeutic agent in a primate model of the disease and create the template for translation into clinical trials.
Tendons Achilles tendon Collagenase-induced tendinopathyMarques2016Lasers Med SciPhotobiomodulation therapy on collagen type I and III, vascular endothelial growth factor, and metalloproteinase in experimentally induced tendinopathy in aged rats.RatOur findings indicate that PBMT may lead to the improvement and acceleration of inflammation when compared to tendinopathy aged group.
Bone Bone repair Oliveira2010J Mater Sci Mater MedLow level laser therapy does not modulate the outcomes of a highly bioactive glass-ceramic (Biosilicate) on bone consolidation in rats.RatOur findings suggest that although Biosilicate exerts some osteogenic activity during bone repair, laser therapy is not able to modulate this process.
Oral Orthodontics Tooth movementCruz2004Lasers Surg MedEffects of low-intensity laser therapy on the orthodontic movement velocity of human teeth: a preliminary study.HumanOur findings suggest that LILT does accelerate human teeth movement and could therefore considerably shorten the whole treatment duration.
Hearing Hearing loss Noise-induced hearing lossTamura2015Neurosci LettLow-level laser therapy for prevention of noise-induced hearing loss in rats.RatOur findings suggest that LLLT has cytoprotective effects against NIHL via the inhibition of iNOS expression and apoptosis.
Joints Osteoarthritis Alfredo2012Clin RehabilEfficacy of low level laser therapy associated with exercises in knee osteoarthritis: a randomized double-blind study.Human RCT/DBOur findings suggest that low level laser therapy when associated with exercises is effective in yielding pain relief, function and activity on patients with osteoarthritis of the knees.
Hearing Hearing loss Noise-induced hearing lossRhee2012J Biomed OptEffect of low-level laser treatment on cochlea hair-cell recovery after acute acoustic trauma.RatOur findings suggest that low-level laser irradiation promotes recovery of hearing thresholds after acute acoustic trauma. Comment: Parameters were insufficiently reported.
Muscle Exercise de Oliveira2014TrialsWhat is the ideal dose and power output of low-level laser therapy (810 nm) on muscle performance and post-exercise recovery? Study protocol for a double-blind, randomized, placebo-controlled trial.Study protocolOur intention, is to determine optimal laser therapy application parameters capable of slowing down the physiological muscle fatigue process, reducing injuries or micro-injuries in skeletal muscle stemming from physical exertion and accelerating post-exercise muscle recovery.
Oral Denture stomatitis Maver-Biscanin2005Photomed Laser SurgEffect of low-level laser therapy on Candida albicans growth in patients with denture stomatitis.HumanOur observations indicate that LLLT might be valuable in the treatment of denture stomatitis.
Pain Myofascial Trigger point painAiraksinen1989Acupunct Electrother ResEffects of the infrared laser therapy at treated and non-treated trigger pointsHuman RCT, crossoverOur research study results suggest that infrared laser had an effect at the trigger points and that the treatment significantly increased the pain threshold.
Tendons Achilles tendon Tendon injuryHaslerud2016Photomed Laser SurgLow-Level Laser Therapy and Cryotherapy as Mono- and Adjunctive Therapies for Achilles Tendinopathy in Rats.RatOur results demonstrate that cryotherapy in combination with LLLT can produce an anti-inflammatory add-on effect. The order of therapy administration seems essential, as superior histology and biomechanical results were found in the cryotherapy first/LLLT group.
Heart Cardiomyocytes Zhang2009J Mol Cell CardiolNear infrared light protects cardiomyocytes from hypoxia and reoxygenation injury by a nitric oxide dependent mechanism.In vitroOur results demonstrate that exposure to NIR at the time of reoxygenation protects neonatal rat cardiomyocytes and HL-1 cells from injury, as assessed by lactate dehydrogenase release and MTT assay. Similarly, indices of apoptosis, including caspase 3 activity, annexin binding and the release of cytochrome c from mitochondria into the cytosol, were decreased after NIR treatment. NIR increased NO in cardiomyocytes, and the protective effect of NIR was completely reversed by the NO scavengers carboxy-PTIO and oxyhemoglobin, but only partially blocked by the NO synthase (NOS) inhibitor L-NMMA. Mitochondrial metabolism, measured by ATP synthase activity, was increased by NIR, and NO-induced inhibition of oxygen consumption with substrates for complex I or complex IV was reversed by exposure to NIR. Taken together these data provide evidence for protection against hypoxia and reoxygenation injury in cardiomyocytes by NIR in a manner that is dependent upon NO derived from NOS and non-NOS sources.
Respiratory system Lung inflammation Airway inflammation caused by LPS injectionAimbire2005Lasers Med SciEffect of LLLT Ga-Al-As (685 nm) on LPS-induced inflammation of the airway and lung in the rat.RatOur results demonstrate that LLLT produced anti-inflammatory effects on RTHR, BAL and lung neutrophils influx in association with inhibition of COX-2-derived metabolites.
Nerves PNS Schwann cellsYazdani2012J Photochem Photobiol BEffects of low level laser therapy on proliferation and neurotrophic factor gene expression of human schwann cells in vitro.In vitroOur results demonstrate that low level laser therapy stimulate human schwann cell proliferation and NGF gene expression in vitro.
Oral Oral mucositis Antunes2008Med Oral Patol Oral Cir BucalThe Impact of low power laser in the treatment of conditioning-induced oral mucositis: a report of 11 clinical cases and their review.Case seriesOur results have indicated that the use of LPLT in HSCT patients is a powerful instrument in the treatment of overt OM and is now a standard procedure in this group of patients in our hospital.
Oral Oral mucositis Cost-effectiveness calculationAntunes2016Oral OncolCost-effectiveness of low-level laser therapy (LLLT) in head and neck cancer patients receiving concurrent chemoradiation.Human RCT Our results indicate that morbidity was lower in the Laser Group and that LLLT was more cost-effective than placebo up to a threshold of at least US$ 5000 per mucositis case prevented. Jan Tuner has written: PBM to prevent and reduce the incidence of oral mucositis has been well documented for 15 years and still not being widely accepted. Now that there is evidence of a cost saving method we might experience a renewed interest, because Money Talks.
Nerves CNS Spinal cordAshworth2016BMC NeurosciComparative assessment of phototherapy protocols for reduction of oxidative stress in partially transected spinal cord slices undergoing secondary degeneration.In vitroOur results indicate that R/NIR-LT is an effective antioxidant therapy, and indicate that effective wavelengths and ranges of intensities of treatment can be adapted for a variety of CNS injuries and conditions, depending upon the transmission properties of the tissue to be treated.
Poor science Pain reliefLundeberg1987Acta Physiol ScandA comparative study of the pain-relieving effect of laser treatment and acupuncture.HumanOur results indicate that the analgesic effects reported in humans with similar modes of low power laser might be due to placebo. According to Hode&Tuner, the study was published without the knowledge of Lars Hode. This is interesting, since Hodes name is in the author list. Regarding the researcher: [See additional info]
Tendons Achilles tendon TenotomyGuerra Fda2013Lasers Med SciLLLT improves tendon healing through increase of MMP activity and collagen synthesis.RatOur results indicate that the pulsed LLLT improved the remodeling of the ECM during the healing process in tendons through activation of MMP-2 and stimulation of collagen synthesis.
Brain Depression Xu2016Mol NeurobiolLow-Level Laser Irradiation Improves Depression-Like Behaviors in Mice.MouseOur results revealed that LLLT effectively improved depression-like behaviors, in the two depression mice models, by decreasing immobility duration in behavioral despair tests. In addition, ATP biosynthesis and the level of mitochondrial complex IV expression and activity were significantly elevated in prefrontal cortex (PFC) following LLLT. Intriguingly, LLLT has no effects on ATP content and mitochondrial complex I-IV levels in other tested brain regions, hippocampus and hypothalamus. As a whole, these findings shed light on a novel strategy of transcranial LLLT on depression improvement by ameliorating neurotransmitter abnormalities and promoting mitochondrial function in PFC.
Purinergic signalling Extracellular ATP Wang2015Mediators InflammModulation of extracellular ATP content of mast cells and DRG neurons by irradiation: studies on underlying mechanism of low-level-laser therapy.In vitroOur results show that irradiation led to elevation of extracellular ATP level in the human mast cell line HMC-1 in a dose-dependent manner, which was accompanied by elevation of intracellular ATP content, an indicator for ATP synthesis, together with [Ca(2+)]i elevation, a trigger signal for exocytotic ATP release. In contrast to MCs, irradiation attenuated the extracellular ATP content of neurons, which could be abolished by ARL 67156, a nonspecific ecto-ATPases inhibitor.
Muscle Energy metabolism Albuquerque-Pontes2015Photochem PhotobiolEffect of pre-irradiation with different doses, wavelengths, and application intervals of low-level laser therapy on cytochrome c oxidase activity in intact skeletal muscle of rats.Rat Biphasic dose response (?)Our results show that LLLT increased (p < 0.05) cytochrome c oxidase expression mainly with the following wavelengths and doses: 660 nm with 1 J, 830 nm with 3 J, and 905 nm with 1 J at all time points. We conclude that LLLT can increase cytochrome c oxidase activity in intact skeletal muscle and that it contributes to our understanding of how LLLT can enhance performance and protect skeletal muscles against fatigue development and tissue damage. Comment: At some time points, the Cox expression was lower than in control group. It doesnt seem the result is as straightforward as the abstract makes it seem...
Liver Liver regeneration Hepatectomy -> Liver regenerationAraújo2013Lasers Med SciLiver regeneration following partial hepatectomy is improved by enhancing the HGF/Met axis and Akt and Erk pathways after low-power laser irradiation in rats.RatOur results show that LPLI can improve liver regeneration as shown by increased HGF protein expression and the phosphorylation levels of Met, Akt, and Erk 1/2 accompanied by higher levels of the PCNA and Ki-67 protein in the remnant livers. In summary, our results suggest that LPLI may play a clinical role as a simple, fast, and easy-to-perform strategy in order to enhance the liver regenerative capacity of a small liver remnant after hepatectomy.
Muscle Muscle inflammation Cytokine-induced muscle inflammation Pulsing vs continuous Biphasic dose responseMantineo2014J Biomed OptLow-level laser therapy on skeletal muscle inflammation: evaluation of irradiation parameters.RatOur results show treatment effects, particularly for irradiation with the 830-nm laser. At day 6, the concentration of all measured proinflammatory cytokines in the 30 and 40 mW groups was significantly lower than for the control group. IL-6 concentration was reduced for all treatment groups and TNF-α for all but the 50-mW group. The number of inflammatory cells in muscle tissue samples was also significantly lower in all treatment groups when compared to the control animals
Brain Parkinsons disease TransgenicPurushothuman2013Brain ResThe impact of near-infrared light on dopaminergic cell survival in a transgenic mouse model of parkinsonism.MouseOur results showed immunoreactivity for 4-HNE, 8-OHDG and AT8 within the SNc was increased in K3 mice compared to WT, and that this increase was mitigated by NIr. Results further showed that TH⁺ cell number was lower in K3 mice than in WT, and that this loss was mitigated by NIr. In summary, NIr treatment reduced the oxidative stress caused by the tau transgene in the SNc of K3 mice and saved SNc cells from degeneration. Our results, when taken together with those in other models, strengthen the notion that NIr treatment saves dopaminergic cells in the parkinsonian condition.
Tendons Achilles tendon LED phototherapyXavier2010Lasers Surg MedAnti-inflammatory effects of low-level light emitting diode therapy on Achilles tendinitis in rats.RatOur results showed that LED decreases the inflammatory cells influx and mRNA expression to IL-1 beta, IL-6, tumor necrosis factor-alpha (TNF-alpha) in both phase, and cyclooxygenase-2 (COX-2) just in initial phase (P < 0.05).
Autoimmunity Multiple sclerosis Experimental autoimmune encephalomyelitisGonçalves2016AutoimmunityLow-level laser therapy ameliorates disease progression in a mouse model of multiple sclerosis.MouseOur results showed that LLLT consistently reduced the clinical score of EAE and delayed the disease onset, and also prevented weight loss induced by immunization. Furthermore, these beneficial effects of LLLT seem to be associated with the down-regulation of NO levels in the CNS, although the treatment with LLLT failed to inhibit lipid peroxidation and restore antioxidant defense during EAE. Finally, histological analysis showed that LLLT blocked neuroinflammation through a reduction of inflammatory cells in the CNS, especially lymphocytes, as well as preventing demyelination in the spinal cord after EAE induction. Together, our results suggest the use of LLLT as a therapeutic application during autoimmune neuroinflammatory responses, such as MS.
Cells Proliferation Marques2014Exp Biol Med (Maywood)Evaluation of the photobiomodulation in L929 cell culture.In vitroOur results showed that low-level laser therapy stimulates effect when the energy density is 5 to 3030 J/cm(2) and inhibits effects on energy density 0.1 to 3 J/cm(2). This inhibitory effect was evidenced by the absence of dead cells labeled, decreased cell density, and by the absorption of neutral red in intact cells. The present study demonstrated that LLLT has proliferative and inhibitory effects on L929 cells, depending on the parameters chosen for irradiation, which influence the results. It was also demonstrated that the metabolic condition of the cells dictates the intensity response after irradiation.
Brain Parkinsons disease MPTP LED phototherapyReinhart2015Neurosci Res810nm near-infrared light offers neuroprotection and improves locomotor activity in MPTP-treated mice.MouseOur results showed that MPTP-treated mice that were irradiated with 810nm NIr had both greater locomotor activity (∼40%) and number of dopaminergic cells (∼20%) than those that were not. In summary, 810nm (as with 670nm) NIr offered neuroprotection and improved locomotor activity in MPTP-treated mice.
Brain Parkinsons disease MPTPEl Massri2016Exp Brain ResNear-infrared light treatment reduces astrogliosis in MPTP-treated monkeys.MonkeyOur results showed that NIr treatment reduced dramatically (~75 %) MPTP-induced astrogliosis in both the SNc and striatum. Among microglia, however, NIr had a more limited impact in both nuclei; although there was a reduction in overall cell size, there were no changes in the number of microglia in the MPTP-treated monkeys after NIr treatment.
Oral Orthodontics Nimeri2014Clin Cosmet Investig DentThe effect of photobiomodulation on root resorption during orthodontic treatment.HumanOur results showed that photobiomodulation did not cause root resorption greater than the normal range that is commonly detected in orthodontic treatments.
Muscle Exercise Borges2014Lasers Med SciLight-emitting diode phototherapy improves muscle recovery after a damaging exercise.Our results showed that the muscle soreness, muscle strength loss, and ROM impairments were significantly reduced up to 96 h after a damaging eccentric exercise bout for the LEDT group compared with the PLACEBO group. A single LEDT (630 nm) intervention immediately after a damaging eccentric exercise bout was effective in terms of attenuating the muscle soreness and muscle strength loss and ROM impairments.
Tendons Achilles tendon Da Ré Guerra2016Lasers Med SciLow-level laser therapy modulates pro-inflammatory cytokines after partial tenotomy.RatsOur results showed that the pulsed LLLT seems to exert an anti-inflammatory effect over injured tendons, with reduction of the release of proinflammatory cytokines, such as TNF-α and the decrease in the i-NOS activity. Thanks to the pain reduction and the facilitation of movement, there was a stimulation in the TGF-β and IL-1β release. In conclusion, we believe that pulsed LLLT worked effectively as a therapy to reestablish the tendon integrity after rupture.
Fertility, genitals, etc. Testicle Ahn2013Biomed ResThe effects of low level laser therapy (LLLT) on the testis in elevating serum testosterone level in rats.RatOur results showed that the rate of tissue penetration was significantly higher in the 808 nm wavelength group as compared with the 670 nm wavelength group (P<0.05); serum T level was not significantly higher in the experimental groups as compared with the control group; but serum T level was significantly elevated in the 670 nm wavelength group on day 4. Thus the LLLT using a 670-nm diode laser was effective in increasing serum T level without causing any visible histopathological side effects. In conclusion, the LLLT might be an alternative treatment modality to the conventional types of testosterone replacement therapy. Comment: This finding was published in a very-low impact journal, not indexed by PubMed.
Oral Oral mucositis Genot-Klastersky2008Support Care CancerThe use of low-energy laser (LEL) for the prevention of chemotherapy- and/or radiotherapy-induced oral mucositis in cancer patients: results from two prospective studies.Human RCTOur results strongly support the already available literature, suggesting that LEL is an effective and safe approach to prevent or treat oral mucositis resulting from cancer chemotherapy. Comment: Wavelength was not reported.
Fibromyalgia Armagan2006J Back Musculoskelet RehabilLong-term efficacy of low level laser therapy in women with fibromyalgia: A placebo-controlled studyHuman RCTOur results suggest that LLLT has both short- and long-term effectiveness in the treatment of fibromyalgia.
Edema Paw Inflammatory paw edema PBM vs diclofenac LLLT on lymph nodesMeneguzzo2013Lasers Med SciPrevention and treatment of mice paw edema by near-infrared low-level laser therapy on lymph nodes.MouseOur results suggest that LLLT was able to produce both anti-inflammatory and pro-inflammatory effects depending on to the site and moment of irradiation.
Tendons Achilles tendon Casalechi2013Lasers Med SciLow-level laser therapy in experimental model of collagenase-induced tendinitis in rats: effects in acute and chronic inflammatory phases.RatOur results suggest that LLLT with parameters employed in the present study was able to modulate IL-10, VEGF, MMP1, and MMP13 mRNA gene expression both in acute than in chronic tendon inflammation. However, further studies are needed to establish optimal parameters for LLLT.
Protozoa Paramecium PenetrationAmaroli2016Lasers Med Sci808-nm laser therapy with a flat-top handpiece photobiomodulates mitochondria activities of Paramecium primaurelia (Protozoa).ProtozoaOur results suggest that thanks to flat-top handpiece we used, high fluences by high-powered laser have to be reconsidered as an effective and non-invasive therapy. Possible associated benefits of deeper tissue penetration would increase treatment effectiveness and reduced irradiation time.
Eyes Methanol toxicity LED phototherapyEells2003Proc Natl Acad Sci U S ATherapeutic photobiomodulation for methanol-induced retinal toxicity.RatOur studies document a significant recovery of rod- and cone-mediated function in LED-treated, methanol-intoxicated rats. We further show that LED treatment protected the retina from the histopathologic changes induced by methanol-derived formate. These findings provide a link between the actions of monochromatic red to near-IR light on mitochondrial oxidative metabolism in vitro and retinoprotection in vivo.
Wound healing Wounds Diabetic mice LED phototherapyWhelan2002J Clin Laser Med SurgEffect of NASA light-emitting diode irradiation on molecular changes for wound healing in diabetic mice.MouseOur studies have revealed certain tissue regenerating genes that were significantly upregulated upon LED treatment when compared to the untreated sample. Integrins, laminin, gap junction proteins, and kinesin superfamily motor proteins are some of the genes involved during regeneration process. We believe that the use of NASA light-emitting diodes (LED) for light therapy will greatly enhance the natural wound healing process, and more quickly return the patient to a preinjury/illness level of activity. This work is supported and managed through the Defense Advanced Research Projects Agency (DARPA) and NASA Marshall Space Flight Center-SBIR Program.
Circulation Vasorelaxation Aterosclerotic rabbitKihshidze2000Photochem PhotobiolPhotoactivation of vascular iNOS and elevation of cGMP in vivo: possible mechanism for photovasorelaxation and inhibition of restenosis in an atherosclerotic rabbit models.RabbitOur study demonstrated that intravascular low dose laser irradiation induces iNOS and elevates vascular cGMP in an in vivo atherosclerotic rabbit model. We think that endoluminal laser irradiation of PTCA-treated arteries modulates relaxation, migration and prolif-eration of SMC, which in turn reduces the incidence of restenosis.
Development Embryogenesis Yeager2006J Biochem Mol Toxicol670 nanometer light treatment attenuates dioxin toxicity in the developing chick embryo.Our study demonstrates that 670 nm phototherapy can mitigate the oxidative stress and energy deficit resulting from developmental exposure to TCDD while reducing TCDD-induced embryo mortality. Moreover, LED treatment restores hepatic enzyme activities to control levels in TCDD-exposed embryos. The effective attenuation of TCDD-induced embryo toxicity by LED treatment could extend to mitigating the effects of other teratogens that induce oxidative and energy stress. Comment: According to the figure, LLLT seemed to increase mortality at some dioxin dosages... I wonder why this isnt mentioned in the abstract.
Penetration Pitzschke2015Phys Med BiolRed and NIR light dosimetry in the human deep brain.Human cadaverOur study demonstrates that it is possible to illuminate deep brain tissues transcranially, transsphenoidally and via different application routes. This opens therapeutic options for sufferers of PD or other cerebral diseases necessitating light therapy.
Pain Analgesia Meireles2012Rev DorRole of endogenous opioids in 820 nm low power laser analgesia in the knees of Wistar ratsRatOur study has observed that low power 820 nm laser analgesic effect has suffered significant interference and was antagonized by naloxone. To justify such effect, it is inferred that the group receiving naloxone and low power laser association has maintained pain in intra-group comparison for the third evaluation moment. It is then believed that laser might have induced endogenous opioids production and release by blood cells15, thus explaining our results.
Skin Rejuvenation Skin rejuvenation (wrinkles etc)Lee2007J Photochem Photobiol BA prospective, randomized, placebo-controlled, double-blinded, and split-face clinical study on LED phototherapy for skin rejuvenation: clinical, profilometric, histologic, ultrastructural, and biochemical evaluations and comparison of three different treatment settings.Human split-face studyOur study results showed that LED phototherapy is an effective treatment for skin rejuvenation through objectively measured data and histological and ultrastructural bodies of evidence of increased collagen and elastic fibers as well as clinical photographs and double-blinded assessment of the investigators and the subjects.
Brain Brain injury Xuan2014J Biomed OptTranscranial low-level laser therapy enhances learning, memory, and neuroprogenitor cells after traumatic brain injury in mice.MouseOur study results suggest that tLLLT may improve TBI both by reducing cell death in the lesion and by stimulating neurogenesis.
Fibromyalgia Gür2002Rheumatol IntEffects of low power laser and low dose amitriptyline therapy on clinical symptoms and quality of life in fibromyalgia: a single-blind, placebo-controlled trial.Human RCT/SBOur study suggests that both amitriptyline and laser therapies are effective on clinical symptoms and QOL in fibromyalgia and that Ga-As laser therapy is a safe and effective treatment in cases with FM. Additionally, the present study suggests that the Ga-As laser therapy can be used as a monotherapy or as a supplementary treatment to other therapeutic procedures in FM.
Fibromyalgia Gür2002Lasers Med SciEfficacy of low power laser therapy in fibromyalgia: a single-blind, placebo-controlled trial.Human RCT/SBOur study suggests that laser therapy is e#ective on pain, muscle spasm, morning sti#ness, and total tender point number in fibromyalgia and suggests that this therapy method is a safe and e#ective way of treatment in the cases with fibromyalgia.
Hearing Tinnitus Salahaldin2012ISRN OtolaryngolLow-level laser therapy in patients with complaints of tinnitus: a clinical study.Human Over half of the patients (56.9%) had some form of improvement in their tinnitus symptoms. Mild improvement was reported in 33.8% of patients, moderate improvement was reported in 16.9%, and full improvement was reported in 6.15%.
Oral Burning mouth syndrome Valenzuela & Lopez-Jornet2016J Oral RehabilEffects of low-level laser therapy on burning mouth syndrome.Human RCTOverall improvements in VAS scores from baseline to the end of treatment were: Group I 15.7%; Group II 15.6%; Group III placebo 7.3%.
Joints Osteoarthritis HIRO 3.0 device HILTAlayat2017Lasers Med SciEfficacy of pulsed Nd:YAG laser in the treatment of patients with knee osteoarthritis: a randomized controlled trial.Human RCTOverall, pulsed Nd:YAG laser combined with GCS and exercises was more effective than GCS + EX and exercises alone in the treatment of KOA patients.
Skin Peptides Hochman2014Lasers Med SciLow-level laser therapy and light-emitting diode effects in the secretion of neuropeptides SP and CGRP in rat skin.RatP was released in Infrared Laser Group (p = 0.01); there was no difference in the CGRP secretion among groups. Infrared (808 nm) LLLT enhances neuropeptide [substance P] secretion in healthy rat skin.
Dermatology Telangiectasia Green light vs LLLTTierney & Hanke2009Lasers Surg MedRandomized controlled trial: Comparative efficacy for the treatment of facial telangiectasias with 532 nm versus 940 nm diode laser.Human RCT/SB (?) Split-facePain associated with the laser treatment was rated as significantly less for the 940 nm wavelength relative to the 532 nm wavelength. Erythema post-treatment was significantly less with 940 nm relative to 532 nm. Significant crusting and swelling were only reported with the 532 nm wavelength. The mean percentage improvement with the 940 nm wavelength (63.0%) was greater than that achieved with the 532 nm wavelength (47.8%) (P<0.05). On photographic evaluation, 940 nm was significantly more efficacious for larger caliber vessels than 532 nm. Both wavelengths were equally efficacious for smaller caliber vessels.
Oral Tooth extraction Wisdom tooth Combined wavelengthsEshghpour2016J Oral Maxillofac SurgIs Low-Level Laser Therapy Effective in the Management of Pain and Swelling After Mandibular Third Molar Surgery?Human RCT/DBPain level was significantly lower in the laser than in the placebo side at all time points during the experiment (P < .05). Swelling was significantly lower in the laser than in the placebo group on days 2, 4, and 7 after surgery (P < .05).
Nerves Diabetic neuropathy Yamany & Sayed2012J Adv ResEffect of low level laser therapy on neurovascular function of diabetic peripheral neuropathyHuman RCT/SBPain was significantly decreased (p ⩽ 0.05) and electrophysiological parameters and foot skin microcirculation were significantly improved (p ⩽ 0.05) in the laser group, while no significant change was obtained in the control group. Low level laser therapy within the applied parameters and technique could be an effective therapeutic modality in reducing pain and improving neurovascular function in patients with diabetic polyneuropathy. Comment: The parameters were poorly reported. The other parts of paper seem fine.
Circulation Brain Cerebral blood flowSalgado2015Lasers Med SciThe effects of transcranial LED therapy (TCLT) on cerebral blood flow in the elderly women.HumanPaired t-test results showed that there was a significant improvement after TCLT with increase in the systolic and diastolic velocity of the left middle cerebral artery (25 and 30%, respectively) and basilar artery (up to 17 and 25%), as well as a decrease in the pulsatility index and resistance index values of the three cerebral arteries analyzed (p < 0.05). TCD parameters showed improvement in the blood flow on the arteries analyzed. TCLT promoted a blood and vasomotor behavior of the basilar and middle cerebral arteries in healthy elderly women.
Oral Oral mucositis Zanin2010Photomed Laser SurgUse of 660-nm diode laser in the prevention and treatment of human oral mucositis induced by radiotherapy and chemotherapy.HumanPatients in group L usually did not present with OM or pain, but all patients in group C presented with OM ranging from Level I to III associated with pain. Comment: Cool results, but parameters arent very well reported.
Dermatology Herpes labialis LLLT vs aciclovirde Carvalho2010Lasers Med SciEffect of laser phototherapy on recurring herpes labialis prevention: an in vivo study.HumanPatients in the experimental group presented a significant decrease in dimension of herpes labialis lesions (P = 0.013) and inflammatory edema (P = 0.031). The reduction in pain level (P = 0.051) and monthly recurrences (P = 0.076) did not reach statistical significance. This study represents an in vivo indication that this treatment should be further considered as an effective alternative to therapeutic regimens for herpes labialis lesions.
Lymphedema Dirican2011Support Care CancerThe short-term effects of low-level laser therapy in the management of breast-cancer-related lymphedema.Human ObservationalPatients with BCRL received additional benefits from LLLT when used in conjunction with standard lymphedema treatment. These benefits include reduction in limb circumference, pain, increase in range of motion and scar mobility. Additionally, two cycles of LLLT were found to be superior to one in this study.
Oral Orthodontics Tooth movementGonçalves2016Lasers Med SciExperimental tooth movement and photobiomodulation on bone remodeling in rats.RatPBM applied in one or three sessions increased the population of osteoblasts. Still, the application of three sessions of PBM increased the density of collagen fibers and new bone formation compared to the controls. An increase was observed in the interincisal distance in irradiated groups with three PBM sessions and the application of force for both 7 or 14 days. These findings suggest that PBM can contribute positively to the orthodontic movement.
Toxins Snake venom Franco2016Lasers Med SciEffect of photobiomodulation on endothelial cell exposed to Bothrops jararaca venom.In vitroPBM at 660 and 780 nm wavelength was able to increase cellular viability and decrease the release of LDH and the loss of cellular integrity. In addition, the concentration of pro-inflammatory cytokine IL1-β was reduced after PBM by both wavelengths. The data reported herein indicates that irradiation with red or near-infrared laser resulted in protection on endothelial cells after exposure to Bothrops venom and could be, at least in part, a reasonable explanation by the beneficial effects of PBM inhibiting the local effects induced by Bothrops venoms, in vivo.
Oral Wound healing Wagner2016Lasers Med SciPhotobiomodulation regulates cytokine release and new blood vessel formation during oral wound healing in rats.RatPBM increased the tissue levels of IL-1β at the early stage of oral wound healing (p < 0.01) and increased the tissue levels of TNF-α during all stages of oral wound healing (p < 0.05). PBM at a dose of 4 J/cm(2) produced more significant results regarding cytokine modulation and was associated with higher MVD at day 5. Collectively, these findings indicate that cytokine modulation and increased angiogenesis are among the basic mechanisms whereby PBM improves oral wound repair.
Surgery (flap) TRAM flap das Neves2016 epubLasers Med SciLaser photobiomodulation (830 and 660 nm) in mast cells, VEGF, FGF, and CD34 of the musculocutaneous flap in rats submitted to nicotine.RatPBM with a wavelength of 830 nm increased the viability of the TRAM flap, with a smaller area of necrosis, increased number of mast cells, and higher expression of VEGF and CD34. PBM increases the viability of musculocutaneous flaps treated with to nicotine. Note: The photograph quality is low.
Nerves Spinal cord Byrnes2005Lasers Surg MedLight promotes regeneration and functional recovery and alters the immune response after spinal cord injury.RatPBM, with 6% power penetration to the spinal cord depth, significantly increased axonal number and distance of regrowth (P < 0.001). PBM also returned aspects of function to baseline levels and significantly suppressed immune cell activation and cytokine/chemokine expression. Our results demonstrate that light, delivered transcutaneously, improves recovery after injury and suggests that light will be a useful treatment for human SCI. Star: Parameters were well reported and results were interesting.
Lymphedema LED phototherapy LED array (16)Storz2016Photodermatol Photoimmunol PhotomedPhotobiomodulation Therapy in breast cancer-related lymphedema: a randomized placebo-controlled trial.Human RCT/DBPBMT using a compactly designed treatment regime in combination with a cluster laser device did not significantly improve quality of life, pain scores, grip strength and limb volume over the time course. A too high amount of total energy applied per point could be a possible explanation for our results. It’s particularly worth mentioning, that we increased the energy dose in order to cut the total amount of sessions. So it’s hard to determine, whether the applied doses are really too high or whether the amount of sessions is simply insufficient. [...] We assume that in treating chronic conditions such as lymphedema, the application of our chosen energy dose and density simply constituted a too strong stimulus in a too short time frame. Star: The parameters and treatment methods were exceptionally well reported in a table.
Oral Oral mucositis Lopes2009Support Care CancerCyclooxygenase-2 and vascular endothelial growth factor expression in 5-fluorouracil-induced oral mucositis in hamsters: evaluation of two low-intensity laser protocols.HamsterPeak severity of mucositis was reduced in the 35 mW laser group as compared to the 100 mW laser and control groups. This reduced peak clinical severity of mucositis in the 35 mW laser group was accompanied by a significantly lower level of COX-2 staining. The 100 mW laser did not have an effect on the severity of clinical mucositis, but was associated with a decrease in VEGF levels at the later time-points, as compared to the other groups.
Diabetes mellitus Ulcers and wounds Mathur2016Lasers Med SciLow-level laser therapy as an adjunct to conventional therapy in the treatment of diabetic foot ulcers.Human RCTPercentage ulcer area reduction was 37 ± 9% in the LLLT group and 15 ± 5.4% in the control group (p < 0.001).
Bone Bone repair Orthodontic mini-implant in tibia boneOmasa2012Photomed Laser SurgLow-level laser therapy enhances the stability of orthodontic mini-implants via bone formation related to BMP-2 expression in a rat model.RatPeriotest values were significantly lower (0.79- to 0.65-fold) and the volume of newly formed bone was significantly higher (1.53-fold) in the LLLT group. LLLT also stimulated significant BMP-2 gene expression in peri-implant bone (1.92-fold). LLLT enhanced the stability of mini-implants placed in rat tibiae and accelerated peri-implant bone formation by increasing the gene expression of BMP-2 in surrounding cells.
Oral Orthodontics Inflammatory responseYanaguizawa2016 epubPhotomed Laser SurgEffects of Low-Level Laser Therapy in Orthodontic Patients on Immediate Inflammatory Response After Mini-Implants Insertion: A Preliminary Report.HumanPGF around nonirradiated mini-implants showed higher levels of IL-8. Levels of IL-6 24 h after mini-implant insertion were higher for laser group. LLLT modulates the initial inflammation after the insertion of mini-implant, possibly increasing the mini-implant success prognostic and decreasing patient discomfort.
Pain Mechanisms AnalgesiaChow2007J Peripher Nerv Syst830 nm laser irradiation induces varicosity formation, reduces mitochondrial membrane potential and blocks fast axonal flow in small and medium diameter rat dorsal root ganglion neurons: implications for the analgesic effects of 830 nm laser.In vitroPhotoacceptors in the mitochondrial membrane absorb laser and mediate the transduction of laser energy into electrochemical changes, initiating a secondary cascade of intracellular events. In neurons, this results in a decrease in MMP with a concurrent decrease in available ATP required for nerve function, including maintenance of microtubules and molecular motors, dyneins and kinesins, responsible for fast axonal flow. Laser-induced neural blockade is a consequence of such changes and provide a mechanism for a neural basis of laser-induced pain relief. The repeated application of laser in a clinical setting modulates nociception and reduces pain. The application of laser therapy for chronic pain may provide a non-drug alternative for the management of chronic pain. [See additional info]
Cells Protection Chemotherapy (vinblastine)Hodgson2011Photomed Laser SurgEffect of photobiomodulation on vinblastine-poisoned murine HERS cells.In vitroPhotobiomodulation demonstrated an improvement in proliferation and glutathione levels in vinblastine-poisoned murine HERS cells.
Muscle Exercise Pinto2016J Strength Cond ResPhotobiomodulation Therapy Improves Performance and Accelerates Recovery of High-Level Rugby Players in Field Test: A Randomized, Crossover, Double-Blind, Placebo-Controlled Clinical Study.Human RCT/DBPhotobiomodulation therapy significantly (p ≤ 0.05) improved the average time of sprints and fatigue index in BST. Photobiomodulation therapy significantly decreased percentage of change in blood lactate levels (p ≤ 0.05) and perceived fatigue (p ≤ 0.05). Pre-exercise PBMT with the combination of super-pulsed laser (low-level laser), red LEDs, and infrared LEDs can enhance performance and accelerate recovery of high-level rugby players in field test. This opens a new avenue for wide use of PBMT in real clinical practice in sports settings.
Mechanisms Original research Isolated liver mitochondriaYu1997Photochem PhotobiolPhotomodulation of oxidative metabolism and electron chain enzymes in rat liver mitochondria.In vitroPhotoirradiation significantly increased oxygen consumption (0.6 J/cm2 and 1.2 J/cm2, P < 0.05), phosphate potential, and the energy charge (1.8 J/cm2 and 2.4 J/cm2, P < 0.05) of rat liver mitochondria and enhanced the activities of NADH: ubiquinone oxidoreductase, ubiquinol: ferricytochrome C oxidoreductase and ferrocytochrome C: oxygen oxidoreductase (0.6 J/cm2, 1.2 J/cm2, 2.4 J/cm2 and 4.8 J/cm2, P < 0.05). The activities of succinate ubiquinone oxidoreductase, ATPase, and lactate dehydrogenase were not affected by photoirradiation. Note: A highly cited article (238 in Google Scholar in 10/2016).
Oral Oral mucositis LED phototherapyHodgson2012Support Care CancerAmelioration of oral mucositis pain by NASA near-infrared light-emitting diodes in bone marrow transplant patients.Human RCT & DB?Phototherapy demonstrated a significant reduction in patient-reported pain as measured by the WHO criteria in this patient population included in this study. Improvement trends were noted in most other assessment measurements.
Cells Protection Diabetes / hypoxia / woundSekhejane2011Photomed Laser SurgIrradiation at 636 nm positively affects diabetic wounded and hypoxic cells in vitro.In vitroPhototherapy resulted in hastened wound closure, increased proliferation, and normalization of cellular function. The decrease in the different pro-inflammatory cytokines and NF-κB translocation was model and time dependent. Overall, laser irradiation resulted in a reduction in inflammatory cytokines and directed cells into the cell survival pathway.
Nerves Diabetic neuropathy LED phototherapy LED clusterArnall2006Acta DiabetolThe restorative effects of pulsed infrared light therapy on significant loss of peripheral protective sensation in patients with long-term type 1 and type 2 diabetes mellitus.HumanPILT improved peripheral protective sensation (PPS) even in patients with long-standing chronic neuropathies whose initial pre-study sensation was not measurable with a 200-g SWM. PILT significantly improves PPS. While the exact mechanism of action is not understood, infrared light may improve peripheral neuropathies by improving foot perfusion by stimulating nitric oxide production. Comment: Parameters were poorly reported.
Oncology Tumor cells Polychromatic lightKnyazev2015Photomed Laser SurgDownregulation of tumorogenicity and changes in the actin cytoskeleton of murine hepatoma after irradiation with polychromatic visible and IR light.In vitro (--> transplanted to mice)Polychromatic light of a wide range of doses did not change the viability and proliferation of cells. After transplantation of cells irradiated with VIS-IR light (4.8 and 9.6 J/cm(2)) and VIS light (38.4 J/cm(2)) the tumor volume was lower in the treated group than in the control group in vivo. Transplantability of the irradiated cells also decreased, whereas survival of tumor-bearing mice increased.
Eyes Ivandic & Ivandic2015Photomed Laser SurgEffects of Photobiomodulation Therapy on Patients with Primary Open Angle Glaucoma: A Pilot Study. [RETRACTED ARTICLE]HumanPoor visual acuity (≤ 20/25), initially found in 24 of 63 eyes (38.1%), improved in 17 (70.8%) eyes and did not change in 7 eyes (29.2%). Mean IOP dropped from 24.9 ± 14.9 to 15.0 ± 6.5 mm Hg (-39.7%, p < 0.001). Visual fields were either fully restored, improved by at least 10 degrees, or remained unchanged in 32, 29, and 2 of 63 eyes (51%, 46%, and 3%), respectively. Mean M-VEP latency was reduced by 13.5 msec (-8%, p < 0.001); mean amplitude increased by +677 nV (+14%, p < 0.001). Adverse effects were not observed. No changes were noted in control eyes. This first small series of cases indicated that photobiomodulation might be a safe approach to lower IOP and to improve visual acuity and fields in eyes with POAG. RETRACTION NOTICE: The second author of the article, Dr. Tomislav Ivandic, notified the Journal that inaccuracies in the reported parameters were discovered after publication of the article as a consequence of the information being translated from German (the authors native language) into English. As a very serious repercussion of this error, Dr. Ivandic states that, Further studies or application based on these false doses would probably harm the eye. The first-named author of the article, Dr. Boris Ivandic, disagrees with this declaration and states that, there is no mistake in the dose calculations using the parameters 10 mW power, 3 mm2 beam spot area as well as 30 or 90 sec time of irradiation, respectively. Photomedicine and Laser Surgery is dedicated to upholding the integrity of the science it publishes. As a result of this irreconcilable dispute between the authors, the editorial leadership of the Journal is officially retracting this article from the literature in an effort to reduce any potential for iatrogenic injury in the event that the erroneous information was used to study or treat other patients. The authors regret this very unfortunate circumstance.
Nerves PNS Nerve injury n. ischiadicusShamir2001J Reconstr MicrosurgDouble-blind randomized study evaluating regeneration of the rat transected sciatic nerve after suturing and postoperative low-power laser treatment.RatPositive somatosensory evoked responses were found in 69.2 percent of the irradiated rats (p = 0.019), compared to 18.2 percent of the non-irradiated rats. Immunohistochemical staining in the laser-treated group showed an increased total number of axons (p = 0.026), and better quality of the regeneration process, due to an increased number of large-diameter axons (p = 0.021), compared to the non-irradiated control group.
Muscle Exercise Dose responseAver Vanin2016Photomed Laser SurgPre-Exercise Infrared Low-Level Laser Therapy (810 nm) in Skeletal Muscle Performance and Postexercise Recovery in Humans, What Is the Optimal Dose? A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.Human RCT/DBPre-exercise LLLT, mainly with 50 J dose, significantly increases performance and improves biochemical markers related to skeletal muscle damage and inflammation. However, LLLT had no effect in decreasing DOMS. No differences (p > 0.05) were found for 30 J dose in any of the outcomes measured. Comment: Since six sites were irradiated, 50J group refers to the 300J total dose.
Muscle Exercise Muscle performance and recovery LED phototherapy LED clusterAntonialli2014Lasers Med SciPhototherapy in skeletal muscle performance and recovery after exercise: effect of combination of super-pulsed laser and light-emitting diodes.Human RCT/DBPre-exercise phototherapy with combination of low-level laser and LEDs, mainly with 30 J dose, significantly increases performance, decreases DOMS, and improves biochemical marker related to skeletal muscle damage. Comment: The parameters are quite complex in this study - read the full text for further information. Star: An interesting paper with parameters well reported and good outcome!
Eyes (Preconditioning)Sun2015Lasers Med SciPre-exposure to low-power diode laser irradiation promotes cytoprotection in the rat retina.RatPre-exposure to a 60-mW (34.27 J/cm(2) on the retina) power laser irradiation stimulates a hyperexpression of Hsp70 together with a hypoexpression of cleaved caspase 3 in rat retina, which may suggest a cellular protective effect. Higher-power laser induced some apoptosis but no other injury: No retinal hemorrhage, necrosis, atrophy, or detachment was observed microscopically with HES staining 20 h after irradiation of 80 mW (44.88 J/cm2 on the retina).
Pain Analgesia Ponnudurai1988Acupunct Electrother ResLaser photobiostimulation-induced hypoalgesia in rats is not naloxone reversible.RatPre-treatment with low dose naloxone (2 mg/kg) did not reverse the hypoalgesic effect of LPBS. High dose naloxone (20 mg/kg) reversed only partially, but significantly, the hypoalgesic effect of LPBS measured by hot-plate, but not that measured by the tail-flick technique. These data suggest that mechanisms other than endogenous opioids may be involved in LPBS-induced hypoalgesia.
Eyes Light-induced damage PreconditioningMarco2013Am J Neurodegener DisThe time course of action of two neuroprotectants, dietary saffron and photobiomodulation, assessed in the rat retina.RatPreconditioning the retina with saffron or PBM reduced photoreceptor death, preserved the population of surviving photoreceptors and reduced the upregulation of GFAP in Müller cells. At the daily dose of saffron used (1 mg/kg), protection was detectable at 2 d, increasing to 10 d. At the daily dose of PBM used (5 J/cm(2) at 670 nm) protection was detectable at 5 d, increasing to 7-10 d.
Eyes Oxygen-induced damageAlbarracin2013BMC Neurosci670 nm light mitigates oxygen-induced degeneration in C57BL/6J mouse retina.MousePretreatment with 670 nm red light reduced expression of markers of oxidative stress and C3, and slowed, but did not prevent, photoreceptor loss over the time course of hyperoxia exposure.
Oral Oral mucositis Patients with head/neck cancer (chemoradiotherapy)Antunes2013Radiother OncolPhase III trial of low-level laser therapy to prevent oral mucositis in head and neck cancer patients treated with concurrent chemoradiation.Human RCT/DBPreventive LLLT in HNSCC patients receiving chemoradiotherapy is an effective tool for reducing the incidence of grade 3-4 OM. Efficacy data were corroborated by improvements seen in quality of life. At a median follow-up of 18 months (10–48 months) differences favoring the LLLT patients were observed in locoregional disease control, progression-free (P = 0.097) or overall survival (P = 0.147; Fig. 3 and 4 of the Supplementary Data). Star: The 18-month follow-up data was supplied.
Oral Oral mucositis Patients with lymphoblastic leukemia A: prevention of OM B: treatment of OM Red vs NIRde Castro2013Photomed Laser SurgLow-level laser in prevention and treatment of oral mucositis in pediatric patients with acute lymphoblastic leukemia.Human (control group)Prophylactic laser produced a better outcome than when patients did not receive any preventive intervention red laser (660 nm) was better than infrared (830 nm)
Wound healing Burns 2nd degree burnEzzati2010Photomed Laser SurgLow-level laser therapy with a pulsed infrared laser accelerates second-degree burn healing in rat: a clinical and microbiologic study.RatPulsed LLLT with 11.7 J/cm(2)/890 nm of a deep second-degree burn model in rat significantly increased the rate of wound closure compared with control burns. Comment: The paper says they used 70-watt output, but it is more likely it was 70 milliwatts.
Wound healing Burns 3rd degree burnEzzati2009J Rehabil Res DevLow-level laser therapy with pulsed infrared laser accelerates third-degree burn healing process in rats.RatPulsed LLLT with 11.7 J/cm(2)/890 nm of a third-degree burn in a rat model significantly increased wound-closure rate compared with control burns. Comment: The paper says they used 70-watt output, but it is more likely it was 70 milliwatts.
Muscle Muscle injury Surgically induced injuryCressoni2008Photomed Laser SurgThe effects of a 785-nm AlGaInP laser on the regeneration of rat anterior tibialis muscle after surgically-induced injury.RatQuantitative data showed that the number of both polymorphonuclear and mononuclear leukocytes in the inflammatory infiltrate at the injury site was smaller in the ILI(1), ILI(2), and ILI(4) subgroups compared with their respective control subgroups (IN(1), IN(2), and IN(4)) for sessions 1, 2, and 4, respectively (p < 0.05). With regard to the regeneration of muscle fibers following injury, only after the fourth treatment session was it possible to find muscle precursor cells such as myoblasts and some myotubes in the ILI(4) subgroup.
Circulation Angiogenesis Cutaneous wounds LED phototherapy LLLT vs LEDde Sousa2013Lasers Med SciLaser and LED phototherapies on angiogenesis.RatQuantitative results showed that green LED (λ530 ± 20 nm), red LED (λ700 ± 20 nm), λ790 nm laser and λ660 nm laser caused significant increased angiogenesis when compared to the control group. It is concluded that both laser and LED light are capable of stimulating angiogenesis in vivo on cutaneous wounds and that coherence was not decisive on the outcome of the treatment.
Circulation Artery collateralization Lohr2013J Mol Cell CardiolFar red/near infrared light treatment promotes femoral artery collateralization in the ischemic hindlimb.Rabbit Mouse In vitroR/NIR significantly increased collateral vessel number which could not be attenuated with L-NAME. R/NIR induced collateralization was abolished with c-PTIO. In vitro, NO production increased in endothelial cells with R/NIR exposure, and this finding was independent of NOS inhibition. Similarly R/NIR induced proliferation and tube formation in a NO dependent manner. Finally, nitrite supplementation accelerated R/NIR collateralization in wild type C57Bl/6 mice. In an eNOS deficient transgenic mouse model, R/NIR restores collateral development.
Joints Rheumatoid arthritis (human synoviocytes)Yamaura2009Lasers Surg MedLow level light effects on inflammatory cytokine production by rheumatoid arthritis synoviocytes.In vitroRadiation at 810 nm (5 J/cm(2)) given before or after TNF-alpha decreases the mRNA level of TNF-alpha and IL-1beta in RA synoviocytes. This treatment using 25 J/cm(2) also decreases the intracellular levels of TNF-alpha, IL-1beta, and IL-8 protein but did not affect the levels of seven other cytokines/chemokines. TNF-alpha-induced activation of NF-kappaB is not altered by 810 nm radiation using 25 J/cm(2).
Brain Cognitive performance Barrett & Gonzalez-Lima2013NeuroscienceTranscranial infrared laser stimulation produces beneficial cognitive and emotional effects in humans.Human RCTReaction time in a sustained-attention psychomotor vigilance task (PVT) was significantly improved in the treated (n=20) vs. placebo control (n=20) groups, especially in high novelty-seeking subjects. Performance in a delayed match-to-sample (DMS) memory task showed also a significant improvement in treated vs. control groups as measured by memory retrieval latency and number of correct trials. The Positive and Negative Affect Schedule (PANAS-X), which tracks self-reported positive and negative affective (emotional) states over time, was administered immediately before treatment and 2 weeks after treatment. The PANAS showed that while participants generally reported more positive affective states than negative, overall affect improved significantly in the treated group due to more sustained positive emotional states as compared to the placebo control group. These data imply that transcranial laser stimulation could be used as a non-invasive and efficacious approach to increase brain functions such as those related to cognitive and emotional dimensions.
LLLT: past and future Bakeeva1993Mol Biol (Mosk).[Formation of gigantic mitochondria in human blood lymphocytes under the effect of an He-Ne laser]. [Article in Russian]Reconstruction of mitochondria from ultrathin sections through the whole lymphocyte showed that 1 h after the irradiation the number of mitochondria was reduced to 9-12 compared to 40-45 in the control cells. In the irradiated lymphocytes 2-4 branching giant mitochondria were revealed instead of small discrete mitochondria in the control cells. Other 6-7 mitochondria were found to retain their shape and volume. It is suggested that the giant mitochondria are formed by fusion of small mitochondria. Formation of giant mitochondria may reflect the increase in the energy exchange level.
Wound healing Wounds Nussbaum2014Photonics Lasers MedEffects of low intensity laser irradiation during healing of infected skin wounds in the rat.RatRed light improved healing of wounds. Only one 808-nm light protocol enhanced healing; lack of benefit using the remaining 808-nm light protocols may have been due to stimulatory effects of the light on S. aureus growth.
Voice Vocal fatigue LED phototherapy LED arrayKagan & Heaton2016J VoiceThe Effectiveness of Low-Level Light Therapy in Attenuating Vocal Fatigue.HumanRed light significantly normalized the combination of PTP, IPSV, and RFF measures compared to other conditions. The red setting heats the neck surface to approximately 43.3°C, whereas the IR setting heats the neck surface to 35.5°C based on a thermometer Results indicate that red light may be effective in improving acoustic, aerodynamic, and self-perceptual markers of vocal fatigue. Although these findings indicate that LLLT is a promising treatment for vocal fatigue, future work is needed to determine optimal light doses, whether wavelengths are more efficacious in combination vs isolation, and when the doses should be applied relative to phonotrauma (before, after, or both) for providing fatigue resistance or hastening recovery. LLLT is a simple, potentially efficacious treatment for vocal fatigue that could have wide clinical relevance to populations with voice disorders or occupations with high voice use demands.
Lymphedema Kaviani2006Lasers Med SciLow-level laser therapy in management of postmastectomy lymphedema.HumanReduction in limb circumference was detected in both groups, although it was more pronounced in the laser group up to the end of 22nd week. Desire to continue treatment at each session and baseline score in the laser group was greater than in the sham group in all sessions. Pain reduction in the laser group was more than in the sham group except for the weeks 3 and 9. No substantial differences were seen in other two parameters between the two treatment groups.
Oral Osteonecrosis da Guarda2012Photomed Laser SurgLaser GaAlAs (λ860 nm) photobiomodulation for the treatment of bisphosphonate-induced osteonecrosis of the jaw.Case reportReduction in painful symptoms was reported after the second irradiation session, and tissue healing was complete at the end of the third week following oral curettage. The patient was followed up for 12 months and exhibited good oral health and quality of life.
Respiratory system Allergic asthma Silva2014Respir Physiol NeurobiolLow-level laser therapy inhibits bronchoconstriction, Th2 inflammation and airway remodeling in allergic asthma.MouseReduction of [bronchial hyperresponsiveness] post LLLT coincided with lower RhoA expression in bronchial muscle as well as reduction in eosinophils and eotaxin. LLLT also diminished ICAM expression and Th2 cytokines as well as signal transducer and activator of transduction 6 (STAT6) levels in lungs from challenged mice. Our results demonstrated that LLLT reduced [bronchial hyperresponsiveness] via RhoA and lessened allergic lung inflammation via STAT6. Comment: In this study, the authors refer to many russian human studies on LLLT and airways.
Oral Periodontium Experimental periodontitis LED phototherapyChang2013J Periodontal ResIrradiation by light-emitting diode light as an adjunct to facilitate healing of experimental periodontitis in vivo.RatReduction of inflammation, accelerated collagen deposition and realignment was noted following irradiation with LED light at densities of 10 and 15 J/cm2, and temporary reduction of periodontal bone loss, as well as bundle bone apposition, was noted at day 3 in rats treated with 10 J/cm2 light.
Oncology Tumor cells Gamma radiated cellsRamos Silva2016J BiophotonicsExploring the effects of low-level laser therapy on fibroblasts and tumor cells following gamma radiation exposure.In vitroRegarding tumor cells, no influences of LLLT on cell viability are noticed. Whereas LLLT enhances cell populations in S and G2 /M cell cycle phases for both cellular lines, a decrease in proliferation and increase in senescence was verified only for tumor cells.
Nerves Spinal cord Ando2013J Biomed OptLow-level laser therapy for spinal cord injury in rats: effects of polarization.RatRegardless of the polarization direction, functional scores of SCI rats that were treated with the 808-nm laser irradiation were significantly higher than those of SCI alone group (Group 1) from day 5 after injury. The locomotive function of SCI rats irradiated parallel to the spinal column (Group 3) was significantly improved from day 10 after injury, compared to SCI rats treated with the linear polarization perpendicular to the spinal column (Group 2). There were no significant differences in ATP contents in the injured tissue among the three groups. We speculate that the higher efficacy with parallel irradiation is attributable to the deeper light penetration into tissue with anisotropic scattering.
Pain Shoulder Stergioulas A2008Photomed Laser SurgLow-power laser treatment in patients with frozen shoulder: preliminary results.Human RCT/SBRelative to the placebo group, the active laser group had: (1) a significant decrease in overall, night, and activity pain scores at the end of 4 wk and 8 wk of treatment, and at the end of 8 wk additional follow-up (16 wk post-randomization); (2) a significant decrease in shoulder pain and disability index (SPADI) scores and Croft shoulder disability questionnaire scores at those same intervals; (3) a significant decrease in disability of arm, shoulder, and hand questionnaire (DASH) scores at the end of 8 wk of treatment, and at 16 wk posttreatment; and (4) a significant decrease in health-assessment questionnaire (HAQ) scores at the end of 4 wk and 8 wk of treatment. There was some improvement in range of motion, but this did not reach statistical significance.
Muscle Energy metabolism Biphasic dose responseNguyen2014MitochondrionEffect of near-infrared light exposure on mitochondrial signaling in C2C12 muscle cells.In vitroRepeated NIR light exposure (4 days) appeared to elevate oxidative stress and increase the upstream mitochondrial regulatory proteins AMPK (3.1-fold), p38 (2.8-fold), PGC-1α (19.7%), Sirt1 (26.8%), and reduced RIP140 (23.2%), but downstream mitochondrial regulation/content (Tfam, NRF-1, Sirt3, cytochrome c, ETC subunits) was unaltered. Our data indicates that NIR light alters mitochondrial biogenesis signaling and may represent a mechanistic link to the clinical benefits.
Wound healing Wounds Immunosuppressed wound healing Pulsed vs continuousKeshri2016PLoS OnePhotobiomodulation with Pulsed and Continuous Wave Near-Infrared Laser (810 nm, Al-Ga-As) Augments Dermal Wound Healing in Immunosuppressed Rats.RatResults clearly delineated that 810 nm PBM at 10 Hz was more effective over continuous and 100 Hz frequency in accelerating wound healing by attenuating the pro-inflammatory markers (NF-kB, TNF-α), augmenting wound contraction (α-SM actin), enhancing cellular proliferation, ECM deposition, neovascularization (HIF-1α, VEGF), re-epithelialization along with up-regulated protein expression of FGFR-1, Fibronectin, HSP-90 and TGF-β2 as compared to the non-irradiated controls. Additionally, 810 nm laser irradiation significantly increased CCO activity and cellular ATP contents. Star: Parameters were well reported.
Oral Tooth extraction Pol2016J Craniofac SurgEfficacy of Anti-Inflammatory and Analgesic of Superpulsed Low Level Laser Therapy After Impacted Mandibular Third Molars Extractions.HumanResults indicate that in the treated site SLLLT determines a reduction in pain and swelling statistically significant compared with the control site (P < 0.05). The authors found that the effectiveness of laser therapy is in the first 5 days after surgery, showing a significant reduction of pain and swelling in the treated site than the control site.
Brain Parkinsons disease Neurotoxins LED phototherapyYing2008Brain ResPretreatment with near-infrared light via light-emitting diode provides added benefit against rotenone- and MPP+-induced neurotoxicity.In vitro (striatal and cortical neurons)Results indicate that pretreatment with NIR-LED significantly suppressed rotenone- or MPP(+)-induced apoptosis in both striatal and cortical neurons (P<0.001), and that pretreatment plus LED treatment during neurotoxin exposure was significantly better than LED treatment alone during exposure to neurotoxins. In addition, MPP(+) induced a decrease in neuronal ATP levels (to 48% of control level) that was reversed significantly to 70% of control by NIR-LED pretreatment. These data suggest that LED pretreatment is an effective adjunct preventative therapy in rescuing neurons from neurotoxins linked to PD.
Brain Parkinsons disease MPTP LED phototherapyLiang2008NeuroscienceNear-infrared light via light-emitting diode treatment is therapeutic against rotenone- and 1-methyl-4-phenylpyridinium ion-induced neurotoxicity.In vitroResults indicated that LED treatments twice a day significantly increased cellular ATP content, decreased the number of neurons undergoing cell death, and significantly reduced the expressions of reactive oxygen species and reactive nitrogen species in rotenone- or MPP+-exposed neurons as compared to untreated ones.
Pain Myofascial Biphasic dose responseSimunovic Z1996J Clin Laser Med SurgLow level laser therapy with trigger points technique: a clinical study on 243 patients.Human RetrospectiveResults measured according to VAS/VRS/PTM: in acute pain, diminished more than 70%; in chronic pain more than 60%. Clinical effectiveness (success or failure) depends on the correctly applied energy dose--over/underdosage produces opposite, negative effects on cellular metabolism. We did not observe any negative effects on the human body and the use of analgesic drugs could be reduced or completely excluded. LLLT suggests that the laser beam can be used as monotherapy or as a supplementary treatment to other therapeutic procedures for pain treatment.
Thyroid Hormones Gamma radiationMorcos2015Photochem PhotobiolPhototherapeutic Effect of Low-Level Laser on Thyroid Gland of Gamma-Irradiated Rats.RatResults revealed improvement in thyroid function, liver function and antioxidant levels, and the blood cells count after LLLT.
Cells Protection Wounded fibroblastsHawkins & Abrahamse2006Lasers Surg MedThe role of laser fluence in cell viability, proliferation, and membrane integrity of wounded human skin fibroblasts following helium-neon laser irradiation.In vitroResults show that 5 J/cm(2) stimulates mitochondrial activity, which leads to normalization of cell function and ultimately stimulates cell proliferation and migration of wounded fibroblasts to accelerate wound closure. Laser irradiation can modify cellular processes in a dose or fluence (J/cm(2)) dependent manner.
Wound healing Wounds Gonçalves2010Photomed Laser SurgComparative study of the effects of gallium-aluminum-arsenide laser photobiomodulation and healing oil on skin wounds in wistar rats: a histomorphometric study.RatResults show that the 60 J/cm2 laser was more effective in stimulating angiogenesis. In addition, the 60 J/cm2 and the 30 J/cm2 laser were both more effective in promoting collagen maturation in the scar tissue of rats, respectively
Fertility, genitals, etc. Sperm motility Bovine spermSiqueira2016Lasers Med SciEffects of photobiomodulation therapy (PBMT) on bovine sperm function.In vitroResults showed significant effects depending on power while using 10 min of irradiation on motility parameters and mitochondrial potential. However, no effect was observed using 5 min of irradiation, regardless of power applied. In conclusion, PBMT is effective to modulate bovine sperm function. The effectiveness is dependent on the interaction between power applied and duration of irradiation, showing that these two parameters simultaneously influence sperm function. In this context, when using the same fluency and energy with different combinations of power and time of exposure, we observed distinct effects, revealing that biological effects should be also based on simple parameters rather than only composite parameters such as fluency, irradiance and energy. Laser irradiation of frozen/thawed bovine semen led to an increase on mitochondrial function and motility parameters that could potentially improve fertility rates.
Nerves PNS Gigo-Benato2004Lasers Med SciLow-power laser biostimulation enhances nerve repair after end-to-side neurorrhaphy: a double-blind randomized study in the rat median nerve model.RatResults showed that laser biostimulation induces: (1) a statistically significant faster recovery of the lesioned function; (2) a statistically significant faster recovery of muscle mass; (3) a statistically significant faster myelination of the regenerated nerve fibers. From comparison of the three different types of laser emissions, it turned out that the best functional outcome was obtained by means of pulsed-continuous-combined laser biostimulation.
Tendons Achilles tendon Barbosa2013Lasers Med SciLow-level laser therapy combined with platelet-rich plasma on the healing calcaneal tendon: a histological study in a rat model.RatResults showed that the deposition of collagen type I was higher when treatment with PRP and LLLT was combined, suggesting a faster regeneration of the tendon.
Bone Implants Implantation of poly-L-lactic/polyglycolic acidFreddo2009Lasers Med SciEffect of low-level laser therapy after implantation of poly-L-lactic/polyglycolic acid in the femurs of rats.RatResults showed that the laser irradiation had had a positive photobiomodulation effect on inflammation, confirmed by a better histologic pattern than that of the control group at 3 days and 7 days. Semiquantitative analysis revealed that groups A and B had a histologic score significantly greater than that of the control group at 3 days. At 21 days, histomorphometric analysis revealed a more intense inflammation in the red laser group than in the other groups. We concluded that low-level laser therapy (LLLT) has positive effects on the photobiomodulation of inflammation in the tissues surrounding the poly-L-lactic/polyglycolic acid (PLLA/PGA) bioabsorbable plate. It stimulated vascularization, fibroblast proliferation, and collagen deposition.
Skin Rejuvenation Collagen & wrinkles LED phototherapyBarolet2009J Invest DermatolRegulation of skin collagen metabolism in vitro using a pulsed 660 nm LED light source: clinical correlation with a single-blinded study.Human split-face studyResults yielded a mean percent difference between LED-treated and non-LED-treated HRS of 31% in levels of type-1 procollagen and of -18% in MMP-1. No histological changes were observed. Furthermore, profilometry quantification revealed that more than 90% of individuals showed a reduction in rhytid depth and surface roughness, and, via a blinded clinical assessment, that 87% experienced a reduction in the Fitzpatrick wrinkling severity score after 12 LED treatments. Star: Interesting and quite extensive paper.
Eyes Kaynezhad2016Exp Eye ResOptical monitoring of retinal respiration in real time: 670 nm light increases the redox state of mitochondria.RatRetinae of aged rats exposed to 670 nm for 5 mins showed consistent progressive increases in oxidation of COX 5 mins post exposure.
Oral Tooth replantation Carvalho Edos2012Dent TraumatolRoot surface treatment using diode laser in delayed tooth replantation: radiographic and histomorphometric analyses in rats.RatRoot surface treatments with high-powered diode laser irradiation prior to delayed replantation reduced the occurrence of external root resorption compared to no treatment or sodium fluoride treatment at up to 60 days.
Infections Bacteria Red light vs blue lightLipovsky2010Lasers Surg MedVisible light-induced killing of bacteria as a function of wavelength: implication for wound healing.In vitroROS production following blue (400-500 nm) light illumination was found to be higher than that of red (500-800 nm). Within the blue range, light of 415 nm induced more ROS than 455 nm, which correlated with results obtained for the reduction in colony count of S. aureus and E. coli following illumination using equal intensities of these two wavelengths.
Eyes Optic neuropathy (rotenone) LED phototherapyRojas2008J NeurosciNeuroprotective effects of near-infrared light in an in vivo model of mitochondrial optic neuropathy.RatRotenone induced a decrease in visual function, as determined by changes in the dark-adapted illuminance sensitivity threshold, escape latency and rate of successful trials in a two-choice visual task, compared with vehicle-treated controls. Behavioral impairment correlated with a decrease in retinal and visual pathway metabolic activity, retinal nerve fiber layer thickness and ganglion cell layer cell density. These changes were prevented by NIL treatments in a dose-dependent manner. Whole-brain cytochrome oxidase and superoxide dismutase activities were also increased in NIL-treated subjects in a dose-dependent manner, suggesting an in vivo transcranial effect of NIL. In whole-brain membrane isolates, NIL prevented the rotenone-induced decrease in cell respiration. The results show that NIL treatment can effectively prevent the neurotoxic effects of rotenone and that it might be used in the treatment of neurodegenerative disorders associated with mitochondrial dysfunction.
Intravascular LLLT KazemiKhoo & Ansari2015Lasers Med SciBlue or red: which intravascular laser light has more effects in diabetic patients?HumanSerum [blood sugar] decreased highly significant after ILIB with both red and blue lights (p < 0.0001), but we did not find significant difference between red and blue lights.
Oral Burning mouth syndrome Romeo2010Ann Stomatol (Roma)The low level laser therapy in the management of neurological burning mouth syndrome. A pilot study.Human Pilot studySeventeen patients (68%) had relevant benefits from the treatment with valid reduction of NRS ratings. In 8 cases the differences of NRS rates were not relevant being under the limit of reliability established in study design. In no case there was a worsening of the symptoms.
Muscle Exercise Santos2014Lasers Med SciEffects of pre-irradiation of low-level laser therapy with different doses and wavelengths in skeletal muscle performance, fatigue, and skeletal muscle damage induced by tetanic contractions in rats.RatSeveral LLLT doses showed some positive effects on peak force and time to decay for one or more contractions, but in terms of total work, only 3 J/660 nm and 1 J/905 nm wavelengths prevented significantly (p < 0.05) the development of skeletal muscle fatigue Optimal doses of LLLT significantly delayed the development skeletal muscle performance and protected skeletal muscle tissue against damage. Our findings also demonstrate that optimal doses are partly wavelength specific and, consequently, must be differentiated to obtain optimal effects on development of skeletal muscle fatigue and tissue preservation. Our findings also lead us to think that the combined use of wavelengths at the same time can represent a therapeutic advantage in clinical settings.
Oral Oral mucositis Patients undergoing HSCTFerreira2016Support Care CancerLow-level laser therapy prevents severe oral mucositis in patients submitted to hematopoietic stem cell transplantation: a randomized clinical trial.Human RCTSevere mucositis was found in 40% of the patients (14/35), 3 in the intervention group (17.65%) and 11 in the sham group (61.11%) (p = 0.015).
Heart Heart failure LED phototherapyCapalonga2016Lasers Med SciLight-emitting diode therapy (LEDT) improves functional capacity in rats with heart failure.RatSham and LEDT-HF groups showed higher relative values than the Control-HF group, respectively, for distance covered (27.7 and 32.5 %), time of exercise test (17.7 and 20.5 %), and speed (13.6 and 12.2 %). Note: In this paper, the sham group does not refer to sham-therapy, but instead to sham-HF.
Joints Osteoarthritis MIRE treatment with Anodyne LED pad deviceHsieh2012Arch Phys Med RehabilShort-term effects of 890-nanometer radiation on pain, physical activity, and postural stability in patients with knee osteoarthritis: a double-blind, randomized, placebo-controlled study.Human RCT/PBShort-term 890-nm radiation therapy for patients with knee OA provided no beneficial effect in improving pain, physical activity, and postural stability. Comment: Because of the biphasic dose response, this dose might have been too high by a few orders of magnitude...
Joints Osteoarthritis MIRE treatment with Anodyne LED pad deviceHsieh2012J Orthop Sports Phys TherTherapeutic effects of short-term monochromatic infrared energy therapy on patients with knee osteoarthritis: a double-blind, randomized, placebo-controlled study.Human RCT/PBShort-term MIRE therapy provided no beneficial effects to body functions, activities, participation, and quality of life in patients with knee OA. Comment: Because of the biphasic dose response, this dose might have been too high by a few orders of magnitude...
Respiratory system COPD COPD Muscular performance LED phototherapy LED clusterMiranda2015Lasers Med SciPhototherapy with combination of super-pulsed laser and light-emitting diodes is beneficial in improvement of muscular performance (strength and muscular endurance), dyspnea, and fatigue sensation in patients with chronic obstructive pulmonary disease.HumanSignificant differences were also found for MVIC (104.8 ± 26.0 N · m vs. 87.2 ± 24.0 N · m, p = 0.000), sensation of dyspnea (1 [0-4] vs. 3 [0-6], p = 0.003), and fatigue in the lower limbs (2 [0-5] vs. 5 [0.5-9], p = 0.002) in favor of phototherapy. We conclude that the combination of super-pulsed lasers and LEDs administered to the femoral quadriceps muscle of patients with COPD increased the PT by 20.2% and the TW by 12%. Phototherapy with a combination of super-pulsed lasers and LEDs prior to exercise also led to decreased sensation of dyspnea and fatigue in the lower limbs in patients with COPD. Comment: The parameters are quite complex in this study - read the full text for further information.
Eyes Dry age-related macular degeneration LED phototherapy (Warp10 + Gentlewaves)Merry2016Acta OphthalmolPhotobiomodulation reduces drusen volume and improves visual acuity and contrast sensitivity in dry age-related macular degeneration.Human Case series (n=42)Significant improvement in mean BCVA of 5.90 letters (p < 0.001) was seen on completion of the 3-week treatment and 5.14 letters (p < 0.001) after 3 months. Contrast sensitivity improved significantly (log unit improvement of 0.11 (p = 0.02) at 3 weeks and 3 months (log unit improvement of 0.16 (p = 0.02) at three cycles per degree. Drusen volume decreased by 0.024 mm3 (p < 0.001) and central drusen thickness was significantly reduced by a mean of 3.78 μm (p < 0.001), while overall central retinal thickness and retinal volume remained stable. This is the first study demonstrating improvements in functional and anatomical outcomes in dry AMD subjects with PBM therapy. These findings corroborate an earlier pilot study that looked at functional outcome measures. The addition of anatomical evidence contributes to the basis for further development of a non-invasive PBM treatment for dry AMD. Some extra data on the methods (not written in the actual article): Subjects had their eyes open for the yellow pulsed but closed for the red, perceived by patients as a comfortable glow with their eyes closed and red penetrates well through the closed lids. The red is gently rested on the eyelid/orbit rim so may touch the lid or be very close to it without any pressure.
Wound healing Wounds Byrnes2004Photomed Laser SurgPhotobiomodulation improves cutaneous wound healing in an animal model of type II diabetes.Sand ratSignificant improvement in wound healing histology and wound closure were found following treatment with 4 J/cm(2) (16 mW, 250-sec treatments for 4 consecutive days; p < 0.05). The 4 J/cm(2) dosage significantly improved histology and closure of wounds in the diabetic group in comparison to the non-irradiated diabetic group.
Oncology Tumor cells Dastanpour2015J Lasers Med SciThe effect of low-level laser therapy on human leukemic cells.In vitroSignificant increase in cell proliferation was seen only after two exposures at energy density of 20J/cm2 (P=0.021).
Muscle Sarcopenia Ovaryectomized ratsCorazza2013Lasers Med SciPhototherapy and resistance training prevent sarcopenia in ovariectomized rats.RatSignificant increases (p < 0.05) were noted for the muscle volume of the T (68.1 ± 19.7%), the L (74.1 ± 5.1%), and the LT (68.2 ± 11.5%) groups compared to the C group (60.4 ± 5.5%). There were also significant increases in the concentrations of IGF-1, IL-1, and TNF-α in the muscles of the treated groups (p < 0.05).
Carpal tunnel Carpal tunnel syndrome Lazovic2014Photomed Laser SurgPlacebo-controlled investigation of low-level laser therapy to treat carpal tunnel syndrome.Human RCT/DBSignificant reduction in pain, reduction in the percentage of patients with a positive Tinels sign, and shortening of sensory and motor latency time in the NCS examination was observed in the experimental LLLT group (but not in the control group).
Safety of LLLT McCarthy2010Photomed Laser SurgLong-term safety of single and multiple infrared transcranial laser treatments in Sprague-Dawley rats.RatSingle and multiple applications of transcranial laser therapy with 808-nm CW laser light at a nominal power density of 10 mW/cm(2) at the surface of the cerebral cortex appears to be safe in Sprague-Dawley rats 1 year after treatment.
Ligaments MCL injury Fung2003Lasers Surg MedEffects of a therapeutic laser on the ultrastructural morphology of repairing medial collateral ligament in a rat model.RatSingle application of low energy laser therapy increases the collagen fibril size of healing MCLs in rats.
Muscle Exercise LED phototherapy LED clusterFerraresi2015J BiophotonicsLight-emitting diode therapy in exercise-trained mice increases muscle performance, cytochrome c oxidase activity, ATP and cell proliferation.MouseSix bi-daily training sessions LEDT-After and LEDT-Before-After regimens more than doubled muscle performance and increased ATP more than tenfold. The effectiveness of LEDT on improving muscle performance and recovery suggest applicability for high performance sports and in training programs. Star: Parameters are well reported. Results are interesting. A photograph is supplied.
Nerves PNS Biphasic dose responseGigo-Benato2010Lasers Surg MedEffects of 660 and 780 nm low-level laser therapy on neuromuscular recovery after crush injury in rat sciatic nerve.RatSix hundred sixty nanometer LLLT either using 10 or 60 J/cm² restored muscle fiber, myelin and nerve fiber CSA compared to the normal group (N).
Development Embryogenesis LED phototherapy DioxinYeager2006Photomed Laser SurgBrief report: embryonic growth and hatching implications of developmental 670-nm phototherapy and dioxin co-exposure.ChickenSize and hatching times suggest that the hatching success and preparedness of chicks developmentally exposed to dioxin concentrations above the lethality threshold is improved by 670-nm LED treatment administered throughout the gestation period, but the relationship may be complicated by an LED-oil interaction.
Gene expression Fonseca2014Laser PhysLow intensity infrared laser affects expression of oxidative DNA repair genes in mitochondria and nucleusIn vitroSkin and muscle tissue of Wistar rats exposed to laser radiation show different expression of POLγ and APEX2 mRNA depending of the fluence and time after exposure. Our study suggests that a low intensity infrared laser affects expression of genes involved in repair of oxidative lesions in mitochondrial and nuclear DNA.
Dermatology Radiation dermatitis MLS(®) laser therapyCensabella2016Support Care CancerPhotobiomodulation for the management of radiation dermatitis: the DERMIS trial, a pilot study of MLS(®) laser therapy in breast cancer patients.Human Pilot studySkin toxicity was equivalent between the groups before the start of LT but significantly differed at the end of radiotherapy, with an aggravation in the control but not in the LT group (e.g., 29 versus 3 % of RTOG grade 2 RD, respectively, P < 0.005). We found no significant group differences with respect to quality of life. However, the RISRAS subjective score decreased in the LT group only, implying a decreased impact of RD on patients quality of life. Finally, patients ratings were significantly higher for LT than for standard care.
Oral Salivary glands Diabetes Antioxidant systemIbuki2013Lasers Med SciLaser irradiation affects enzymatic antioxidant system of streptozotocin-induced diabetic rats.RatSOD and CAT activities, as well as [total antioxidant value] were higher in SMG of irradiated diabetic rats. However, in [submandibular salivary gland] of non-diabetic rats, laser irradiation decreased [total antioxidant] values and led to an increase in the CAT activity. In addition, there was a decrease in the activity of CAT in [parotid gland] of diabetic and non-diabetic animals after laser irradiation.
Hearing Tinnitus Teggi2009Audiol NeurootolTransmeatal low-level laser therapy for chronic tinnitus with cochlear dysfunction.Human RCT/DBSoft laser therapy demonstrated no efficacy as a therapeutic measure for tinnitus.
Oral Oral mucositis Eduardo Fde2015Pediatr TransplantOral mucositis in pediatric patients undergoing hematopoietic stem cell transplantation: clinical outcomes in a context of specialized oral care using low-level laser therapy.Human ObservationalSpecialized oral care, including LLLT, is feasible and affordable for HSCT pediatric patients, although some adaptation in the patients oral hygiene routine must be adopted with help from parents/companions and clinical staff.
Wound healing Pressure ulcer ParametersLanzafame2007Lasers Surg MedReciprocity of exposure time and irradiance on energy density during photoradiation on wound healing in a murine pressure ulcer model.MouseSpecific combinations of parameters were necessaryto achieve accelerated wound healing despite the delivery ofthe same total daily energy density to all wounds. Variationof exposure time and irradiance may account for conflictingresults in the literature. This study appears to confirmearlier in vitro studies demonstrating that the provisionof multiple treatments per day is more effective than thetraditional strategy of delivering a single treatment perday. Further investigations directed at identifying dose–response curves for specific tissues and cell lines should beconducted. Comment: This kind of research of different parameters is important. Hopefully more of similar studies will be conducted.
Brain Microglia Biphasic dose responsevon Leden2013Lasers Surg Med808 nm wavelength light induces a dose-dependent alteration in microglial polarization and resultant microglial induced neurite growth.In vitroSpecifically, PBM with energy densities between 4 and 30 J/cm(2) induced expression of M1 markers in microglia. Markers of the M2 phenotype, including CD206 and TIMP1, were observed at lower energy densities of 0.2-10 J/cm(2)
Fertility, genitals, etc. Sperm motility Human spermSalman Yazdi2014Lasers Med SciEffect of 830-nm diode laser irradiation on human sperm motility.In vitroSperm motility of the control groups significantly decreased after 30, 45 and 60 min of irradiation, while those of irradiated groups remained constant or slightly increased by passing of time. Significant increases have been observed in doses of 4 and 6 J/cm(2) at the times of 60 and 45 min, respectively. SCD test also revealed a non-significant difference.
Oral Periodontium Makhlouf2012Photomed Laser SurgEffect of adjunctive low level laser therapy (LLLT) on nonsurgical treatment of chronic periodontitis.Human Split-mouth DBSRP combined with LLLT improved radiographic bone density and short-term PPD reduction in patients with chronic periodontitis, but did not significantly affect either the gingival crevicular fluid of IL-1β or the gingival or plaque index.
Wound healing Ulcers Saltmarche AE2008Int Wound JLow level laser therapy for healing acute and chronic wounds - the extendicare experience.HumanStaff rated low level laser, easy to learn and use, effective for the majority of their residents worth the additional time. Staff requested a continuation of low level laser even after study completion.
Wound healing Leprosy Barreto & Salgado2010BMC Infect DisClinic-epidemiological evaluation of ulcers in patients with leprosy sequelae and the effect of low level laser therapy on wound healing: a randomized clinical trial.Human RCTStatistical analysis of the data determined that there were no significant differences in the variables analyzed before and after treatment with low level laser therapy.
Pain Back pain RadiculopathyKonstantinovic2010Photomed Laser SurgAcute low back pain with radiculopathy: a double-blind, randomized, placebo-controlled study.Human RCT/DBStatistically significant differences were found in all outcomes measured (p < 0.001), but were larger in [LLLT group] than in [nimesulide group] (p < 0.0005) and [nimesulide + sham-LLLT group] (p < 0.0005). The results in [nimesulide + sham-LLLT group] were better than in [nimesulide group] (p < 0.0005).
Oral Surgery PeriodontologyOzturan2011J Clin PeriodontolCoronally advanced flap adjunct with low intensity laser therapy: a randomized controlled clinical pilot study.Human RCT Split-mouth PilotStatistically significant differences were observed between test and control sites in the gingival recession depth (GRD), gingival recession width (GRW) and width of the keratinized tissue (WKT) and clinical attachment level (CAL) measurements after 1 year (p = 0.014, p = 0.015, p = 0.009 and p = 0.018 respectively). The test group presented greater complete root coverage (n = 7, 70%) compared with the control group (n = 3, 30%) after treatment. Within the limitations of this study, the results indicated that LILT may improve the predictability of CAF in multiple recessions.
Muscle Exercise Muscle growth LLLT clusterBaroni2014Eur J Appl PhysiolEffect of low-level laser therapy on muscle adaptation to knee extensor eccentric training.Human RCTSubjects from [training + LLLT group] reached significantly higher percent changes compared to subjects from [training group] for sum of muscles thicknesses (15.4 vs. 9.4%), isometric peak torque (20.5 vs. 13.7%), and eccentric peak torque (32.2 vs. 20.0%). Star: Interesting results. A topic worth investigating. Comment: LLLT spot size or energy density was not reported.
Oral Endodontics Shiba2009J EndodNeodymium-doped yttrium-aluminium-garnet laser irradiation abolishes the increase in interleukin-6 levels caused by peptidoglycan through the p38 mitogen-activated protein kinase pathway in human pulp cells.In vitroSuppression of the phosphorylated p38 activity by low-power laser irradiation in HP cells culminates in inhibition of the increase in IL-6 induced by peptidoglycan, suggesting that low-power laser irradiation regulates intracellular signaling molecule activities to exert its anti-inflammatory effect. Comment: The parameters were strangely reported. Wavelength is unclear, though Nd:YAG seems to usually be 1064 nm.
Hair Chemotherapy-induced alopeciaWikramanayake2013Lasers Med SciLow-level laser treatment accelerated hair regrowth in a rat model of chemotherapy-induced alopecia (CIA).MouseTaken together, our results demonstrated that LLL treatment significantly accelerated hair regrowth after CIA without compromising the efficacy of chemotherapy in our rat model. Star: Results are very interesting, and a photograph is supplied. Comment: Parameters were poorly reported.
Bone Bone metabolism Alveolar boneSayuri Suzuki2016J BiophotonicsLow-level laser therapy stimulates bone metabolism and inhibits root resorption during tooth movement in a rodent model.RatTaken together, our results indicate that LLLT can stimulate bone remodeling reducing root resorption in a rat model. LLLT improves tooth movement via bone formation and bone resorption in a rat model.
Cells Energy metabolism Osteosarcoma cell lineTsai2015Photodiagnosis Photodyn TherLow-level light therapy potentiates NPe6-mediated photodynamic therapy in a human osteosarcoma cell line via increased ATP.In vitroTaken together, these results demonstrate that LLLT potentiates NPe6-mediated PDT via increased ATP synthesis and is a potentially promising strategy that could be applied in clinical PDT.
Nerves PNS Nerve injury Sciatic nerve Biphasic dose responseWang2014PLoS OneLow-level laser irradiation improves functional recovery and nerve regeneration in sciatic nerve crush rat injury model.RatTaken together, these results suggest that 808-nm LLLT at a low energy density (3 J/cm(2) and 8 J/cm(2)) is capable of enhancing sciatic nerve regeneration following a crush injury.
Liver Minimal hepatic encephalopathy LED phototherapy Cytochrome oxidaseArias2016Lasers Med SciLow-light-level therapy as a treatment for minimal hepatic encephalopathy: behavioural and brain assessment.RatTaking these findings into account, an improvement in the PH + LLLT group due to LLLT treatment should show not only a correct acquisition of the behavioural task, indicated by the behavioural differences between PH and PH + LLLT and their absence when compared to the SHAM group, but also a decrease in C.O., due to an improvement in the enzyme activity produced by the LLLT treatment, and similarities between brain networks. [For more information, read additional info]
Skin Acne vulgaris Red vs NIRAziz-Jalali2012Indian J DermatolComparison of Red and Infrared Low-level Laser Therapy in the Treatment of Acne Vulgaris.Human RCT/SBTen weeks after treatment acne lesion were significantly decreased in the side treated by 630 nm LLLT (27.7±12.7 to 6.3±1.9) (P<0.001), but this decrease was not significant in the site treated by 890 nm LLLT (26.9±12.4 to 22.2±8.5) (P>0.05).
Oral Periodontium Diabetes + chronic periodontitisDemirturk-Gocgun2017Photomed Laser SurgRole of Low-Level Laser Therapy as an Adjunct to Initial Periodontal Treatment in Type 2 Diabetic Patients: A Split-Mouth, Randomized, Controlled Clinical Trial.Human split-mouthTest sites showed significant improvement in PI and BOP in deep pockets at the 1-month follow-up period (p < 0.001 and <0.001, respectively), whereas no difference was found between the control and the test sites in other periodontal parameters. LLLT during periodontal treatment offered minimal short-term additional benefit in deep pocket healing in patients with type 2 DM.
Muscle Exercise da Costa Santos2014Lasers Med SciLED therapy or cryotherapy between exercise intervals in Wistar rats: anti-inflammatory and ergogenic effects.RatThe [passive rest] group presented a high frequency of necrosis, but the LED group had fewer necrotic areas. Edema formation was prevented, and fewer areas of inflammatory cells were observed in the LED group. The time to exhaustion was greater in both the LED and Cryo groups, without differences in CK levels. CRP was decreased in LED animals. We conclude that LED therapy and cryotherapy can improve performance, although LED therapy is more efficient in preventing muscle damage and local and systemic inflammation. Comment: Results are very interesting. Parameters werent well reported, though.
Muscle Exercise Electrical stimulation of musclede Almeida2011Photochem PhotobiolLow-level laser therapy improves skeletal muscle performance, decreases skeletal muscle damage and modulates mRNA expression of COX-1 and COX-2 in a dose-dependent manner.RatThe 1.0 and 3.0 J groups showed significant enhancement (P < 0.01) in total work performed in six tetanic contractions compared with control group. All laser groups, except the 3.0 J group, presented significantly lower post-exercise CK activity than control group. Additionally, 1.0 J group showed increased COX-1 and decreased COX-2 mRNA expression compared with control group and 0.1, 0.3 and 3.0 J laser groups (P < 0.01). Comment: Parameters were raported in a nice way.
Oral Oral mucositis THOR Model LX2M LED phototherapy LED cluster (69) Extraoral Pediatric patientsTreister2016Photomed Laser SurgA Feasibility Study Evaluating Extraoral Photobiomodulation Therapy for Prevention of Mucositis in Pediatric Hematopoietic Cell Transplantation.HumanThe 10 trained nurses all reported that the device was accessible, maneuverable, and lightweight, and that training was effective. There was no reported toxicity attributed to the PBT.
Dermatology Herpes labialis LED phototherapyHargate2006Clin Exp DermatolA randomised double-blind study comparing the effect of 1072-nm light against placebo for the treatment of herpes labialisHuman RCT/DBThe 1072-nm light-emitting diode device reduced cold-sore healing time to 6.3 days compared with 9.4 days for placebo (P = 0.048).
Muscle Exercise Biphasic dose response (?)Larkin-Kaiser2016Lasers Med SciPhotobiomodulation delays the onset of skeletal muscle fatigue in a dose-dependent manner.Human RCTThe 240-J dose significantly extended TTF by 26 % (p = 0.032) compared with the sham dose. TTF for the 240-J dose was strongly associated with a decrease in muscle fatigue (R (2) = 0.54, p = 0.024). Our findings show that a 240-J dose of NIR light therapy is efficacious in delaying the onset and extent of muscle fatigue during submaximal isometric positioning tasks. Our findings suggest that NIR light therapy may be used as an ergogenic aid during functional tasks or post-injury rehabilitation. Comment: The 480J dose was less effective.
Peritoneum Peritonitis Correa2007Photomed Laser SurgLow-level laser therapy (GaAs lambda = 904 nm) reduces inflammatory cell migration in mice with lipopolysaccharide-induced peritonitis.MouseThe 3-J/cm(2) exposure group showed the best results at 24 hours, with reductions of 77% in neutrophil and 49% in leukocyte counts. Low-level laser therapy (904 nm) can reduce inflammatory cell migration in mice with LPS-induced peritonitis in a dose-dependent manner. Note: The single dose was given in three parts, within 3h.
Wavelengths Blue & Green Human adipose-derived stem cellsWang2016Sci RepPhotobiomodulation (blue and green light) encourages osteoblastic-differentiation of human adipose-derived stem cells: role of intracellular calcium and light-gated ion channels.In vitroThe 420 nm and 540 nm wavelengths were more effective in stimulating osteoblast differentiation compared to 660 nm and 810 nm. Intracellular calcium was higher after 420 nm and 540 nm, and could be inhibited by capsazepine and SKF96365, which also inhibited osteogenic differentiation. We hypothesize that activation of light-gated calcium ion channels by blue and green light could explain our results.
Muscle Exercise Dose responsePerini2016Lasers Med SciLong-term low-level laser therapy promotes an increase in maximal oxygen uptake and exercise performance in a dose-dependent manner in Wistar rats.RatThe 61.2 J/cm(2)-LLLT group increased VO2basal (~40 %), VO2max (~24 %), VCO2max (~17 %), and distance covered (~34 %) after LLLT application on the skeletal muscle. No significant results were found comparing before and after conditions for the studied variables considering P-LLLT and 8.7 J/cm(2)-LLLT groups. The LLLT promoted in a dose-dependent manner an increase in oxygen consumption uptake and a performance increment of male Wistar rats. Comment: Parameters were well reported.
Bone Osteoclastogenesis Lee2016Photomed Laser SurgRegulation of RANKL-Induced Osteoclastogenesis by 635-nm Light Emitting Diode Irradiation Via HSP27 in Bone Marrow-Derived Macrophages.In vitroThe 635-nm irradiation treatment significantly increased HSP27 expression and decreased intracellular ROS generation, as well as p38 and AKT phosphorylation, leading to reductions in the expression of c-fos, NFATc1, and DC-STAMP and TRAP activation and osteoclastic bone resorption in RANKL-induced BMMs. However, in HSP27-silenced BMMs, no change was observed.
Oral Oral mucositis Schubert2007Support Care CancerA phase III randomized double-blind placebo-controlled clinical trial to determine the efficacy of low level laser therapy for the prevention of oral mucositis in patients undergoing hematopoietic cell transplantation.Human RCT/DBThe 650 nm wavelength reduced the severity of oral mucositis and pain scores. Low level laser therapy was well-tolerated and no adverse events were noted. Comment 1: On the other hand, the 780 nm wavelength appeared to make things even worse... Comment 2: The Discussion part seems lengthy. Maybe worth reading.
Nerves PNS Yan2011J Peripher Nerv SystInhibitory effects of visible 650-nm and infrared 808-nm laser irradiation on somatosensory and compound muscle action potentials in rat sciatic nerve: implications for laser-induced analgesia.RatThe 650-nm LI decreased SSEP amplitudes and increased latency after 20 min. CMAP proximal amplitudes and hip/ankle (H/A) ratios decreased at 10 and 20 min with increases in proximal latencies approaching significance. The 808-nm LI decreased SSEP amplitudes and increased latencies at 10 and 20 min. CMAP proximal amplitudes and H/A ratios decreased at 10 and 20 min. Latencies were not significantly increased. All LI changes for both wavelengths returned to baseline by 48 h. These results strengthen the hypothesis that a neural mechanism underlies the clinical effectiveness of LLLT for painful conditions.
Edema Paw Inflammatory paw edema by carrageenanAlbertini2007J Photochem Photobiol BAnti-inflammatory effects of low-level laser therapy (LLLT) with two different red wavelengths (660 nm and 684 nm) in carrageenan-induced rat paw edema.RatThe 660 nm and 684 nm laser groups developed significantly (p<0.01) less edema (0.58 ml [SE+/-0.17] ml and 0.76 ml [SE+/-0.10] respectively) than the control group (1.67 ml [SE+/-0.19]) at 4h after injections. Similarly, both laser groups showed a significantly lower number of inflammatory cells in the muscular and conjunctive sub-plantar tissues than the control group. We conclude that both 660 nm and 684 nm red wavelengths of LLLT are effective in reducing edema formation and inflammatory cell migration when a dose of 7.5 J/cm(2) is used.
Oral Dentin hypersensitivity Wavelength comparisonLadalardo2004Braz Dent JLaser therapy in the treatment of dentine hypersensitivity.HumanThe 660 nm red diode laser was more effective than the 830 nm infrared laser and a higher level of desensitization was observed at the 15 and 30 minute post-irradiation examinations. The immediate and late therapeutic effects of the 660 nm red diode laser were more evident in 25-35-year-old patients compared with those of the 830 nm infrared diode laser, in terms of the different age groups.
Protozoa Paramecium Amaroli2015Photomed Laser SurgParamecium: a promising non-animal bioassay to study the effect of 808 nm infrared diode laser photobiomodulation.ProtozoaThe 808 nm infrared diode laser light, at the irradiation parameters used in our work, results in a precocious fission rate in P. primaurelia cells, probably through an increase in metabolic activity, secondary to an energy transfer.
Penetration Tedford2015Lasers Surg MedQuantitative analysis of transcranial and intraparenchymal light penetration in human cadaver brain tissue.Human cadaverThe 808 nm wavelength light demonstrated superior CNS tissue penetration.
Nerves PNS Nerve injury n. ischiadicusRochkind1989NeurosurgeryStimulatory effect of He-Ne low dose laser on injured sciatic nerves of rats.RatThe action potential of the injured sciatic nerves that were laser-irradiated increased to values close to that of a noninjured nerve. The studies include follow-up for 1 year after the injury. This electrophysiological manifestation of the effect of laser treatment on injured nerves was accompanied by a diminution of the size of the scar tissue from these nerves. Yet to be resolved is whether these two phenomena (i.e., electrophysiological and morphological responses) coincide or whether they relate to each other.
Nerves CNS Bells palsy MIRE treatment with Anodyne LED pad deviceNg & Chu2014J Chiropr MedTreatment of Bells Palsy Using Monochromatic Infrared Energy: A Report of 2 Cases.Human Case seriesThe acute case received 19 treatments in 6 weeks. He reported an improvement of 95%. The chronic case received a total of 45 treatments in 9 months. She rated an improvement of 50%. These 2 patients seemed to respond to a different degree to the MIRE therapy. As 71% of patients with Bells palsy recover uneventfully without any treatment, the present study describes the course of care but cannot confirm the effectiveness of MIRE therapy in the management of Bells palsy.
Muscle Muscle injury Ribeiro2016PLoS OneRed and Infrared Low-Level Laser Therapy Prior to Injury with or without Administration after Injury Modulate Oxidative Stress during the Muscle Repair Process.RatThe administration of red and infrared laser therapy at different times positively modulates the activity of antioxidant enzymes and reduces stress markers during the muscle repair process.
Cells Energy metabolism LymphocytesBenedicenti2008Photomed Laser SurgIntracellular ATP level increases in lymphocytes irradiated with infrared laser light of wavelength 904 nm.In vitroThe amount of ATP in irradiated cell cultures was 10.79 +/- 0.15 microg/L (SD; n = 10), and in non-irradiated cell cultures it was 8.81 +/- 0.13 microg/L (SD; n = 10). The average percentage increase of irradiated versus control cell cultures was about 22.4% +/- 0.56% SD (p < 0.001). This significant increase is probably due to laser irradiation; it cannot be attributed to any thermal effect, as the temperature during irradiation was maintained at 37.0 degrees +/- 0.5 degrees C.
Cells Energy metabolism HeLa cellsKaru1995J Photochem Photobiol BIrradiation with He-Ne laser increases ATP level in cells cultivated in vitro.In vitroThe amount of ATP in the log phase of cultured cells remained at the control level (0.79 +/- 0.09) x 10(-15) mol per cell) during the first 15 min after irradiation; it then increased sharply and, after reaching a maximum (170.8%) 20 min after irradiation, decreased slowly to the control level.
Nerves PNS Rochkind2007Photomed Laser SurgLaser phototherapy (780 nm), a new modality in treatment of long-term incomplete peripheral nerve injury: a randomized double-blind placebo-controlled study.Human RCT/DBThe analysis of motor function during the 6-month follow-up period compared to baseline showed statistically significant improvement (p = 0.0001) in the laser-treated group compared to the placebo group. No statistically significant difference was found in sensory function. Electrophysiological analysis also showed statistically significant improvement in recruitment of voluntary muscle activity in the laser-irradiated group (p = 0.006), compared to the placebo group.
Wound healing Burns LLLT vs polychromatic polarized lightOliveira2008Photomed Laser SurgThe use of light photobiomodulation on the treatment of second-degree burns: a histological study of a rodent model.RatThe analysis of the results demonstrated that the damaged tissue was able to efficiently absorb and process the light at all tested wavelengths. LPBM at 660 nm showed better results at early stages of wound healing. However, the use of 780-nm laser light had beneficial effects throughout the experimental period, with the animals growing newly-formed tissue similar to normal dermis. Despite our findings that the use of both types of light energy improved the healing of second-degree burns at the early stages, long-term assessment is needed to verify if this improvement will influence the final results of treatment.
Pain Back pain Laser acupunctureGlazov2014Acupunct MedLow-dose laser acupuncture for non-specific chronic low back pain: a double-blind randomised controlled trial.Human RCT/DBThe analysis showed no difference between sham and the laser groups at 6 weeks for pain or disability.
Oral Endodontics Ramalho2016Lasers Med SciA randomized placebo-blind study of the effect of low power laser on pain caused by irreversible pulpitis.Human RCTThe application of 780-nm diode laser irradiation, at 4 and 40 J/cm2, showed no effect in reducing the pain in SIP in comparison to the placebo group. The fluence of 4 J/cm2 showed a negative effect in local anesthetics, resulting in significant increase of complimentary local anesthesia during emergency endodontic treatment. LPT should be avoided in teeth with pain due to irreversible pulpitis.
Oral Tooth extraction Wisdom toothLópez-Ramírez2012Lasers Med SciEfficacy of low-level laser therapy in the management of pain, facial swelling, and postoperative trismus after a lower third molar extraction. A preliminary study.Human RCT/DBThe application of a low-level laser with the parameters used in this study did not show beneficial affects in reducing pain, swelling, and trismus after removal of impacted lower third molars.
Oncology Tumor cells Jeong, Andrew2016DISSERTATION (Boston University)Safety evaluation of low level light therapy on cancer cellsIn vitroThe application of LLL at 808 nm with energy densities ranging from 0.1 J/cm2 to 10 J/cm2 under an LED source did not induce cell proliferation or death compared to control (0 J/cm2) for each cell line in the absence or the presence of each drug, and no definite trend was observed with increasing energy density. The study suggests that LLLT at these parameters may be safe to use on cancer patients, but further studies on different cancer cell lines and animal models with different parameters (wavelength, energy density, dosage) of LLL are warranted.
Nerves Spinal cord Wu2009Lasers Surg Med810 nm Wavelength light: an effective therapy for transected or contused rat spinal cord.RatThe average length of axonal re-growth in the rats in the light treatment (LT) groups with the hemisection (6.89+/-0.96 mm) and contusion (7.04+/-0.76 mm) injuries was significantly longer than the comparable untreated control groups (3.66+/-0.26 mm, hemisection; 2.89+/-0.84 mm, contusion). The total axon number in the LT groups was significantly higher compared to the untreated groups for both injury models (P<0.05). For the hemisection model, the LT group had a statistically significant lower angle of rotation (P<0.05) compared to the controls. For contusion model, there was a statistically significant functional recovery (P<0.05) in the LT group compared to untreated control. Light therapy applied non-invasively promotes axonal regeneration and functional recovery in acute SCI caused by different types of trauma. These results suggest that light is a promising therapy for human SCI.
Brain Konstantinović2013Lasers Surg MedTranscranial application of near-infrared low-level laser can modulate cortical excitability.HumanThe average MEP size was significantly reduced during the first 20 minutes following the TLS. The pattern was present in 10 (71.5%) of the participants. The MEP size reduction correlated negatively with the motor threshold at rest. TLS with NIR-LLL induced transitory reduction of the excitability of the stimulated cortex.
Wound healing Wounds Ribeiro2009Photomed Laser SurgImmunohistochemical assessment of myofibroblasts and lymphoid cells during wound healing in rats subjected to laser photobiomodulation at 660 nm.RatThe average number of myofibroblasts was statistically significantly higher in the irradiated group than in the non-irradiated group on the eighth (p = 0.001) but not the 14th (p = 0.555) day. B and T cells were significantly more conspicuous in the irradiated group on both the eighth (p = 0.004 and 0.02, respectively) and 14th days (p = 0.04 and 0.03, respectively). Our results suggest that LLLT facilitates myofibroblastic differentiation during the early stages of the cicatricial repair process. Furthermore, LLLT also appears to modulate the inflammatory response by downregulating lymphocytic proliferation during the wound healing process.
Skin Scars LED phototherapyPark2016Dermatol SurgPrevention of Thyroidectomy Scars in Asian Adults With Low-Level Light Therapy.HumanThe average VSS and GAS scores were lower in the treatment group, whereas the subjective score was not significantly different.
Oral Oral mucositis Cotomacio2017J Biomed OptDosimetric study of photobiomodulation therapy in 5-FU-induced oral mucositis in hamsters.HamsterThe best PBMT protocol to maintain lowest OM levels compared to Ch group was L1, followed by L2 and L3. Our results suggest that the application mode of PBMT and the energy delivered per area could interfere with the OM healing.
Oral Oral mucositis LED phototherapy LED vs LLLTFreide Mdo2014Clin Oral InvestigLED and laser photobiomodulation in the prevention and treatment of oral mucositis: experimental study in hamsters.HamsterThe best results were obtained from the preventive laser and LED photobiomodulation groups; both treatments were effective in diminishing the OM lesions. Comment: The laser parameters seem a little bit unlogical. If the radiation time is 30 seconds with the power output of 40mW, then total dose is 1.2J, not 16J.
Tendons Achilles tendon Mårdh & Lund2016J Lasers Med SciHigh Power Laser for Treatment of Achilles Tendinosis - a Single Blind Randomized Placebo Controlled Clinical Study.Human RCTThe between group difference were significant in four of nine questions regarding loading activities of the FAOS subscale. Assessed pain thresholds were found increased in the HPLT group, as compared to the placebo HPLT group. At individual level, the results varied. The results indicate that HPLT may provide a future option for treatment of Achilles tendinosis related pain, but further studies are warranted.
Development Embryogenesis Lim2008J Biochem Mol ToxicolAttenuation of TCDD-induced oxidative stress by 670 nm photobiomodulation in developmental chicken kidney.ChickenThe biochemical indicators of oxidative and energy stress in the kidney were reversed by daily phototherapy, restoring ATP and glutathione contents and increasing antioxidant enzyme activities to control levels. Photobiomodulation also normalized the level of lipid peroxidation increased by TCDD exposure. The results of this study suggest that 670 nm photobiomodulation may be useful as a noninvasive treatment for renal injury resulting from chemically induced cellular oxidative and energy stress.
Bone Bone repair A transverse critical size defect (CSD) to femurRajaei Jafarabadi2016Lasers Med SciThe effects of photobiomodulation and low-amplitude high-frequency vibration on bone healing process: a comparative study.RatThe biostimulation effects of PBM or LLLT and of low-amplitude high-frequency WBV both had a positive impact on bone healing process, for critical size defects in the presence of a stainless steel implant. But their combination, i.e., low-level laser therapy and low-amplitude high-frequency whole body vibration (LV), interestingly did not accelerate the fractured bone healing process.
Oral Mastication Tullberg2003PainEffects of low-power laser exposure on masseter muscle pain and microcirculation.Human RCT/DBThe blood flow did not change significantly in the patients, but increased after active laser exposure and decreased after placebo exposure in the healthy individuals. The difference between active laser and placebo was significant. In conclusion, the results of this study do not support an effect of low-power laser exposure on masseter muscle microcirculation in patients with chronic orofacial pain of muscular origin. Comment: The abstract seems difficult to interpret...
Diabetes mellitus Glycation Peplow & Baxter2014Lasers Surg MedDefining a therapeutic window for laser irradiation (810 nm) applied to the inguinal region to ameliorate diabetes in diabetic mice.MouseThe blood plasma fructosamine level of diabetic mice irradiated with 20.4 J/cm(2) was significantly lower than for nonirradiated controls, whereas that for diabetic mice irradiated with 40.8 J/cm(2) was not significantly different than for nonirradiated controls.
Gene expression Safavi2008Lasers Med SciEffects of low-level He-Ne laser irradiation on the gene expression of IL-1beta, TNF-alpha, IFN-gamma, TGF-beta, bFGF, and PDGF in rats gingiva.RatThe case and control groups did not have a significant difference in the gene expression of TNF-alpha and bFGF (P > 0.05). These findings suggest that low-level He-Ne laser irradiation decreases the amount of inflammation and accelerates the wound healing process by changing the expression of genes responsible for the production of inflammatory cytokines.
Tendons Achilles tendon Tumilty2012Arch Phys Med RehabilClinical effectiveness of low-level laser therapy as an adjunct to eccentric exercise for the treatment of Achilles tendinopathy: a randomized controlled trial.Human RCTThe clinical effectiveness of adding LLLT to eccentric exercises for the treatment of Achilles tendinopathy has not been demonstrated using the parameters in this study. (See Comment & Reply. According to Bjordal&Lopes-Martins, the actual dose was more than 10x smaller than Tumilty et al. reported in their paper.)
Oral Periodontium Qadri2005J Clin PeriodontolThe short-term effects of low-level lasers as adjunct therapy in the treatment of periodontal inflammation.Human Split-faceThe clinical variables i.e. probing pocket depth, plaque and gingival indices were reduced more on the laser side than on the placebo one (p<0.01).
Wound healing Wounds Diabetic rats LLLT vs LED LED phototherapyDall Agnol2009Lasers Med SciComparative analysis of coherent light action (laser) versus non-coherent light (light-emitting diode) for tissue repair in diabetic rats.RatThe coherent and non-coherent lights produced similar effects during a period of 168 h after the lesions had been made. For the group composed of diabetic animals, 72 h after creation of the lesion, it was observed that the therapy with LEDs had been more efficient than that with the laser in the reduction of the wounds diameters.
Skin Cell protection Wavelength combination Biphasic dose responseTian2012Dermatol SurgAntiphotoaging effects of light-emitting diode irradiation on narrow-band ultraviolet B-exposed cultured human skin cells.In vitroThe combination of 630/850- or 660/830-nm irradiation led to better direct and indirect antiphotoaging outcomes than single LED wavelengths in NB-UVB-irradiated cultured normal human skin cells.
Wound healing Pressure ulcer Kazemikhoo2015J Skin Stem CellLow-Level Laser Therapy Along With Intravascular Laser in Deep Pressure Ulcer Resistant to Conventional TherapiesHuman Case reportThe combination of laser therapy with conventional therapy and surgery increases the process of wound healing remarkably, particularly in resistant wound cases. In other words, it accelerates the reconstruction of blood vessels and increases the lesion revascularizations, increases the production and formation of granulation tissue in the wound, eradicates microbial flora, sterilizes the wound pathogens, and facilitates graft surgery repairing success. This process not only leads to a better healing of ulcers, but also prevents recurrent ulcers due to improvement of perfusion in the treated area.
Muscle Exercise Miranda2016J Athl TrainUsing Pre-Exercise Photobiomodulation Therapy Combining Super-Pulsed Lasers and Light-Emitting Diodes to Improve Performance in Progressive Cardiopulmonary Exercise Tests.Human CrossoverThe combination of lasers and LEDs increased the time, distance, and pulmonary ventilation and decreased the score of dyspnea during a cardiopulmonary test.
Skin Acne vulgaris LED phototherapy (w/ blue light)Sadick N2009J Cosmet Laser TherA study to determine the effect of combination blue (415 nm) and near-infrared (830 nm) light-emitting diode (LED) therapy for moderate acne vulgaris.HumanThe combination therapy for acne produced results which were less effective in the reduction of inflammatory lesions than those achieved with the previously reported blue/red combination. Further study with a much larger patient population is warranted.
Wound healing Wounds Rodrigo2009Photomed Laser SurgAnalysis of the systemic effect of red and infrared laser therapy on wound repair.RatThe combined application of red and infrared lasers resulted in the most evident systemic effect on the repair of skin wounds produced in rats.
Joints Osteoarthritis Kim2016J Phys Ther SciThe effects of high intensity laser therapy on pain and function in patients with knee osteoarthritis.Human ControlledThe comparison of the two groups showed that the high intensity laser therapy group had statistically significant lower scores in both the visual analogue scale and the Korean Western Ontario and McMaster Universities Osteoarthritis Index than the conservative physical therapy group. High intensity laser therapy is considered an effective non-surgical intervention for reducing pain in patients with knee osteoarthritis and helping them to perform daily activities. Comment: The important parameters were not reported (wavelength, power output, spot size etc).
Oral Endodontics Bramante2015J EndodUse of a 660-nm Laser to Aid in the Healing of Necrotic Alveolar Mucosa Caused by Extruded Sodium Hypochlorite: A Case Report.Case reportThe conventional treatment protocol was combined with low-level laser therapy. Clinical and radiographic examinations after 7 months revealed complete repair of the necrotic area with no paresthesia and further indicated the integrity of the apical region of the tooth where the extrusion of sodium hypochlorite occurred. Comment: The author didnt report dose parameters.
Oral Oral mucositis Chor2010Eur J HaematolLow-power laser to prevent oral mucositis in autologous hematopoietic stem cell transplantation.LetterThe cumulative probability to develop oral mucositis was 47% in the laser group and 69% in the placebo group (P = 0.27). Comment: Parameters were poorly reported. Control group received LED light...
Nerves PNS Sciatic nerveAlcântara2013Lasers Surg MedEffect of low-level laser therapy (LLLT) on acute neural recovery and inflammation-related gene expression after crush injury in rat sciatic nerve.RatThe current study showed that LLLT increased MMPs activity, mainly MMP-9, and TNF-α protein level during the acute phase of nerve injury, modulating inflammation. Based on these results, it is recommended that LLLT should be started as soon as possible after peripheral nerve injury.
Dermatology Herpes labialis Sergio2013Photochem Photobiol SciTherapeutic low-intensity red laser for herpes labialis on plasmid survival and bacterial transformation.In vitroThe data indicate low-intensity red laser: (i) alters the survival of plasmids in wild type, fpg/mutM(-) and xthA(-)E. coli cultures depending of growth phase, (ii) alters the content of the supercoiled form of plasmids in the wild type and fpg/mutM(-)E. coli cells, (iii) alters the content of nucleic acids and proteins in wild type E. coli cells, (iv) alters the transformation efficiency of plasmids in wild type and fpg/mutM(-)E. coli competent cells. These data could be used to understand positive effects of low-intensity lasers on herpes labialis treatment.
Mechanisms Original research Anders2008IEEE J Sel Top Quantum ElectronLight Supports Neurite Outgrowth of Human Neural Progenitor Cells In Vitro: The Role of P2Y ReceptorsIn vitroThe data presented here establish the neuritogenic potential of light on NHNPCs in a growth factor and serum-free environment. Based on these findings, we propose that the light caused an increase in ATP that acted through P2Y receptors and downstream signaling pathways leading to neurite outgrowth. Note: A correction has been published. The Figure 4 (especially images D, E and F) was incorrect.
Lymphedema Piller&Thelander1998LymphologyTreatment of chronic postmastectomy lymphedema with low level laser therapy: a 2.5 year follow-up.Human Case seriesThe data suggest that laser treatment, at least initially, improved most objective and subjective parameters of arm lymphedema.
Brain Brain injury Xuan2015J BiophotonicsLow-level laser therapy for traumatic brain injury in mice increases brain derived neurotrophic factor (BDNF) and synaptogenesis.MouseThe data suggest that the benefit of LLLT to the brain is partly mediated by stimulation of BDNF production, which may in turn encourage synaptogenesis. Moreover the pleiotropic benefits of BDNF in the brain suggest LLLT may have wider applications to neurodegenerative and psychiatric disorders.
Oral Orthodontics Tooth movementSousa2011Photomed Laser SurgInfluence of low-level laser on the speed of orthodontic movement.HumanThe diode laser used within the protocol guidelines increased the speed of tooth movement. This might reduce orthodontic treatment time.
Oral Oral mucositis Abramoff2008Photomed Laser SurgLow-level laser therapy in the prevention and treatment of chemotherapy-induced oral mucositis in young patients.Human RCTThe ease of use of LLLT, high patient acceptance, and the positive results achieved, make this therapy feasible for the prevention and treatment of OM in young patients.
Edema Paw Inflammatory paw edema PBM vs diclofenacAlbertini2004J Photochem Photobiol BEffects of different protocol doses of low power gallium-aluminum-arsenate (Ga-Al-As) laser radiation (650 nm) on carrageenan induced rat paw ooedema.RatThe ED that produced an anti-inflammatory effect were 1 and 2.5 J/cm(2), reducing the oedema by 27% (P<0.05) and 45.4% (P<0.01), respectively. The ED of 2.5 J/cm(2) produced anti-inflammatory effects similar to those produced by the cyclooxigenase inhibitor sodium diclofenac at a dose of 1 mg/kg. In adrenalectomized animals, the laser irradiation failed to inhibit the oedema.
Oral Tooth extraction Wisdom toothCarrillo1990Int Dent JA randomized double-blind clinical trial on the effectiveness of helium-neon laser in the prevention of pain, swelling and trismus after removal of impacted third molars.Human RCT/DBThe effect of helium-neon (He-Ne) laser on the prevention of pain, swelling and trismus following the removal of an impacted third molar was studied in 100 patients randomly allocated to receive He-Ne laser, ibuprofen or placebo in a prospective double-blind parallel clinical trial. Trismus was significantly reduced in the He-Ne laser and ibuprofen treatment groups. Pain was significantly less in the ibuprofen group with regard to He-Ne laser and placebo groups. Swelling was the same in the three treatment groups.
Pain Surgical Santos Jde2012J Clin NursLow-level laser therapy for pain relief after episiotomy: a double-blind randomised clinical trial.Human RCT/DBThe effect of laser in perineal pain relief was not demonstrated in this study. The dosage may not have been sufficient to provide relief from perineal pain after episiotomy during a vaginal birth.
Nerves PNS Nerve injury n. ischiadicusRochkind2001Lasers Surg MedEffects of laser irradiation on the spinal cord for the regeneration of crushed peripheral nerve in rats.RatThe electrophysiologic activity of the injured nerves (compound muscle action potentials--CMAPs) was found to be approximately 90% of the normal precrush value and remained so for up to a long period of time. In the control nonirradiated group, electrophysiologic activity dropped to 20% of the normal precrush value at day 21 and showed the first signs of slow recovery 30 days after surgery. The two groups were found to be significantly different during follow-up period (P < 0.001). Comment: Parameters were insufficiently reported.
Oral Tooth extraction Wisdom tooth Intraoral+ExtraoralAmarillas-Escobar2010J Oral Maxillofac SurgUse of therapeutic laser after surgical removal of impacted lower third molars.Human RCT/DBThe experimental group exhibited a lower intensity of postoperative pain, swelling, and trismus than the control group, without significant statistical differences. Comment: Parameters were poorly reported.
Circulation Red blood cells Walski2015Photochem Photobiol SciNear infrared light induces post-translational modifications of human red blood cell proteinsIn vitroThe exposure of intact RBCs to NIR light causes quaternary transitions in Hb, dehydration of proteins and decreases the amount of physiologically inactive methemoglobin, as detected by Raman spectroscopy. These effects are accompanied by a lowering of the intracellular pH (pHi) and changes in the cell membrane topography, as documented by atomic force microscopy (AFM). All those changes are in line with our previous studies where alterations of the membrane fluidity and membrane potential were attributed to NIR action on RBCs. The rate of the above listed changes depends strictly on the dose of NIR light that the cells receive, nonetheless it should not be considered as a thermal effect.
Heart MI MI MSCsTuby2009Photomed Laser SurgImplantation of low-level laser irradiated mesenchymal stem cells into the infarcted rat heart is associated with reduction in infarct size and enhanced angiogenesis.RatThe findings of the present study provide the first evidence that LLLT can significantly increase survival and/or proliferation of MSCs post-implantation into the ischemic/infarcted heart, followed by a marked reduction of scarring and enhanced angiogenesis. The mechanisms associated with this phenomenon remain to be elucidated in further studies.
Muscle Energy metabolism Cytochrome oxidase LED phototherapy LED cluster (149x)Hayworth2010Photochem PhotobiolIn vivo low-level light therapy increases cytochrome oxidase in skeletal muscle.RatThe findings showed for the first time that in vivo LLLT induced a dose- and fiber type-dependent increase in cytochrome oxidase in muscle fibers. LLLT was particularly effective at enhancing the aerobic capacity of intermediate and red fibers. The findings suggest that LLLT may enhance the oxidative energy metabolic capacity of different types of muscle fibers, and that LLLT may be used to enhance the aerobic potential of skeletal muscle.
Tendons Cells Tenocyte functionChen2015Lasers Med SciSecond messengers mediating the proliferation and collagen synthesis of tenocytes induced by low-level laser irradiation.In vitroThe findings suggested that LLLT stimulated ATP production and increased intracellular calcium concentration. Directly or indirectly via production of TGF-β1, these second messengers mediated the proliferation of tenocytes and synthesis of collagen.
Bone Implants Khadra M2005Swed Dent J SupplThe effect of low level laser irradiation on implant-tissue interaction. In vivo and in vitro studies.Rat + in vitroThe following conclusions are drawn from the results of these five studies: LLLT can promote bone healing and bone mineralization and thus may be clinically beneficial in promoting bone formation in skeletal defects. It may be also used as additional treatment for accelerating implant healing in bone. LLLT can modulate the primary steps in cellular attachment and growth on titanium surfaces. Multiple doses of LLLT can improve LLLT efficacy, accelerate the initial attachment and alter the behaviour of human gingival fibroblasts cultured on titanium surfaces. The use of LLLT at the range of doses between 1.5 and 3 J/cm2 may modulate the activity of cells interacting with an implant, thereby enhancing tissue healing and ultimate implant success.
Muscle Muscle injury Brunelli2014Lasers Med SciThe effects of 780-nm low-level laser therapy on muscle healing process after cryolesion.RatThe G10 and G50 during the 7 days showed a significant reduction (p < 0.05) of lesion area compared to the CG, without differences between groups treated for 14 and 21 days. The G10 showed an increase of the amount of vessels after 14 days compared to the G50, but not in relation to controls. With regard to the immunohistochemical analyses of the MyoD factor, the G10 and G50 during the 7 days showed higher concentrations of immunomarkers than controls.
Heart Transplants Lukes2005Transplant ProcSinglet oxygen energy illumination during moderate cold ischemia prolongs the survival of concordant hamster xeno-heart transplants.RatThe graft survival of SOE-illuminated ischemic hamster xenografts was 2.34 +/- 0.56 versus 1.15 +/- 0.37 days in the control group (P < .05). All hearts displayed immediate graft function versus 70% in the controls (NS). SOE illumination at lambda 634 nm during moderate cold ischemia (+4 degrees C) can improve the survival of concordant hamster xeno-heart transplants. The exact mechanism(s) are currently unknown, but the effect might in part be exerted by a combination of reduced production of ROS and increased oxidative phosphorylation.
Flatworms Dugesia tigrina Lopes2009Braz J BiolA study of low power laser on the regenerative process of Girardia tigrina (Girard,1850) (Turbellaria; Tricladida; Dugesiidae).Dugesia tigrinaThe head fragment after 1 minute of irradiation presented a better organized tissue scheme, when compared with the other treatments. Aspects of the body fragments submitted to 3 minutes of light treatment were very similar to fragments that had not been injured. It can be concluded that there are changes in the quality of regeneration when treated with low power laser under the conditions mentioned above.
Oral Aphthous stomatitis CO2 laserZand2012Photomed Laser SurgPromoting wound healing in minor recurrent aphthous stomatitis by non-thermal, non-ablative CO(2) laser therapy: a pilot study.Human RCTThe healing period was significantly shorter in ulcers treated by NACLT than in those treated with placebo (p=0.02). The process was not painful and anesthesia was not required.
Joints Osteoarthritis Wang2014Lasers Med SciEffects of low-level laser therapy on joint pain, synovitis, anabolic, and catabolic factors in a progressive osteoarthritis rabbit model.RabbitThe histological assessment of pain and synovitis showed that at least 6-week intermittent irradiation of LLLT could relief knee pain and control synovium inflammation. Gross morphologic inspection and histological evaluation showed that 6 weeks of LLLT could decrease cartilage damage of medical femoral condyle and 8 weeks of LLLT could decrease cartilage damage of medical and lateral femoral condyles and medical tibial plateau. Gene expression analysis revealed two results: At least 6 weeks of LLLT could decrease production of catabolic factors, for example, interleukin 1β (IL-1β), inducible nitric oxide synthase (iNOS), and MMP-3, and slow down the loss of anabolic factors, mainly TIMP-1. Eight weeks of LLLT treatment could slow down the loss of collagen II, aggrecan, and anabolic factors, mainly transforming growth factor beta (TGF-β). The study suggests that LLLT plays a protective role against cartilage degradation and synovitis in rabbits with progressive OA by virtue of the regulation of catabolic and anabolic factors in the cartilage. Comment: It seems the results were quite modest.
Oral Tooth extraction Monea2015BMC Oral HealthBone healing after low-level laser application in extraction sockets grafted with allograft material and covered with a resorbable collagen dressing: a pilot histological evaluation.Human RCTThe histological results of the site treated with LLLT for 21 days, harvested at 60 days after grafting showed abundant new bone formation without any sign of inflammation. The same results were obtained in the control group not before 120 days post-surgery. It can be concluded that LLLT photobiomodulation can reduce the healing time after grafting the extraction socket. Comment: Parameters were poorly reported... Even wavelength was left unmentioned, but the device name (OsseoPulse) was mentioned.
Tendons Achilles tendon Elwakil TF2007Lasers Med SciAn in-vivo experimental evaluation of He-Ne laser photostimulation in healing Achilles tendons.Rabbit tendonsThe histopathological findings suggest the favorable qualitative pattern of the newly synthesized collagen of the regenerating tendons after He-Ne laser photostimulation. The biomechanical results support the same favorable findings from the functional point of view as denoted by the better biomechanical properties of the regenerating tendons after He-Ne laser photostimulation with statistical significance (p
Oral Oral mucositis LED phototherapyWhelan2002J Clin Laser Med SurgNASA light-emitting diodes for the prevention of oral mucositis in pediatric bone marrow transplant patients.HumanThe incidence of UOM was 53%, compared to an expected rate of 70-90%. There was also a 48% and 39% reduction of treated left and right buccal pain, respectively, compared to untreated throat pain at about posttransplant day 7 (p < 0.05). There were no significant differences between sides in OMI or pain. Although more studies are needed, LED therapy appears useful in the prevention of OM in pediatric BMT patients.
Wound healing Wounds Tatmatsu-Rocha2016J Photochem Photobiol BLow-level laser therapy (904nm) can increase collagen and reduce oxidative and nitrosative stress in diabetic wounded mouse skin.The increased production of collagen and decreased oxidative and nitrosative stress suggests that LLLT may be a viable therapeutic alternative in diabetic wound healing. Star: The parameters were exceptionally well reported. Worth a look!
Heart MI MIAd & Oron2001Int J CardiolImpact of low level laser irradiation on infarct size in the rat following myocardial infarction.RatThe infarct size (expressed as percent of total left ventricle area) of the LI rats was 10.1+/-5.8, which was significantly lower (65%; P<0.01) than the infarct size of NLI rats which was 28.7+/-9.6.
Wound healing Burns 3rd degree burnFiório2011J Cosmet Laser TherEffect of incoherent LED radiation on third-degree burning wounds in rats.RatThe inflammatory cells as well as the damaged area at the 8th day after burns were significantly lower for the LED-treated group when compared to control. Furthermore, the LED phototherapy effect on cellular migration was even more pronounced at the 16th day. Our results indicated that the treatment with a LED system was clearly effective in reducing the number of inflammatory cells and improving the healing process in an experimental model of third-degree burnings.
Oral Endodontics odontoblast-like cells (MDPC-23).Turrioni2015Oper DentTransdentinal cell photobiomodulation using different wavelengths.In vitroThe infrared LED irradiation at an energy density of 4 J/cm(2) and red LED at an energy density of 25 J/cm(2) were the most effective parameters for transdentinal photobiomodulation of cultured odontoblast-like cells.
Penetration Esnouf2007Acupunct Electrother ResDepth of penetration of an 850nm wavelength low level laser in human skin.Human skin samplesThe intensity of laser radiation reduced by 66% after being transmitted through a 0.784mm sample of human abdominal tissue. In this study most laser radiation was absorbed within the first 1mm of skin.
Oral Tooth extraction Wisdom toothSierra2016Lasers Surg MedChoosing between intraoral or extraoral, red or infrared laser irradiation after impacted third molar extraction.HumanThe intra-group analyses showed that 808 nm laser applied extra-orally favored reductions in postoperative facial swelling and trismus, although the inter-group comparisons revealed no statistically significant differences.
Wound healing Burns Gupta2015J BiophotonicsSuperpulsed (Ga-As, 904 nm) low-level laser therapy (LLLT) attenuates inflammatory response and enhances healing of burn wounds.RatThe irradiated animals showed a significant reduction in wound area (50%, p < 0.05) on eighth day post-wounding compared with the non-irradiated control animals (18%, p < 0.05) Irradiated group exhibited enhanced DNA, total protein, hydroxyproline and hexosamine contents compared to the control and silver sulfadiazine (reference care) treated groups. LLLT exhibited decreased TNF-α level and NF-kB, and up-regulated protein levels of VEGF, FGFR-1, HSP-60, HSP-90, HIF-1α and matrix metalloproteinases-2 and 9 compared to the controls. In conclusion, LLLT using superpulsed 904 nm laser reduced the inflammatory response and was able to enhance cellular proliferation, collagen deposition and wound contraction in the repair process of burn wounds.
Oncology Tumor cells Kreisler2003Lasers Med SciLow-level 809 nm GaAlAs laser irradiation increases the proliferation rate of human laryngeal carcinoma cells in vitro.In vitroThe irradiated cells revealed a considerably higher proliferation activity. The differences were highly significant up to 72 h after irradiation (Mann-Whitney U test, p < 0.001). A cellular responsiveness of human laryngeal carcinoma cells to low-level laser irradiation is obvious. The cell line is therefore suitable for basic research investigations concerning the biological mechanisms of LLLT on cells.
Uncategorized Dias Schalch2016J BiophotonicsPhotomodulation of the osteoclastogenic potential of oral squamous carcinoma cells.In vitroThe irradiation of SCC9 cells with PBM with an energy density of 4 J/cm2 decreased the pro-osteoclastogenic potential of those cells. This may represent a potential useful side effect of PBM therapy. PBM (using recommended parameters for mucositis treatment) decreases the osteoclastogenic potential of oral squamous carcinoma cells.
Nerves PNS Câmara2011Acta Cir BrasHistological analysis of low-intensity laser therapy effects in peripheral nerve regeneration in Wistar rats.RatThe irradiation with low intensity laser (904nm) influenced positively the regeneration of the sciatic nerve in Wistar rats after being injured by crush (axonotmesis), becoming the nerve recovery more rapid and efficient.
Bone Bone repair Nascimento2010Photomed Laser SurgEffect of low-level laser therapy and calcitonin on bone repair in castrated rats: a densitometric study.RatThe La and CaLa had significantly higher bone mineral density than the control and Ca groups.
Infections Bacteria Silva2013An Bras DermatolLow level laser therapy (AlGaInP) applied at 5J/cm2 reduces the proliferation of Staphylococcus aureus MRSA in infected wounds and intact skin of rats.RatThe laser (AlGaInP), with a dose of 5J/cm2 in both intact skin and in wounds of rats infected with Staphylococcus aureus MRSA, is shown to reduce bacterial proliferation.
Cells Protection Wound healing LED phototherapy / laserSpitler & Berns2014J Biomed OptComparison of laser and diode sources for acceleration of in vitro wound healing by low-level light therapy.In vitroThe laser and LED sources were found to be comparable when equal doses of light were applied. The biological response measured was similar in most cases.
Oral Oral mucositis Patients undergoing HSCTSilva2015Photomed Laser SurgThe Impact of Low-Level Laser Therapy on Oral Mucositis and Quality of Life in Patients Undergoing Hematopoietic Stem Cell Transplantation Using the Oral Health Impact Profile and the Functional Assessment of Cancer Therapy-Bone Marrow Transplantation Questionnaires.Human RCTThe laser group presented less severe OM than the control group (p<0.001). LLLT did not influence the oral and general health-related QoL of patients undergoing HSCT, although it was clinically effective in reducing the severity of chemotherapy-induced OM.
Oral Oral mucositis Patients receiving chemoradiotherapy Head&neck cancerOton-Leite2015Lasers Surg MedEffect of low-level laser therapy on chemoradiotherapy-induced oral mucositis and salivary inflammatory mediators in head and neck cancer patients.Human RCTThe laser group showed a reduction in the severity of OM, which coursed with significantly diminished salivary concentration of EGF and VEGF in the 7th radiotherapy session and of IL-6 and FGF in the 35th. There was a trend for reduced levels of IL-1β, TNF-α, IL-10, TGF-β, MMP2/TIMP2, MMP9/TIMP2 in the laser group compared to the control, however, no statistically significant differences were found. These findings demonstrated that LLLT was effective in reducing the severity of chemoradiotherapy-induced OM and was associated with the reduction of inflammation and repair.
Tendons Achilles tendon Collagenase-induced tendinitisTorres-Silva2015Lasers Med SciThe low level laser therapy (LLLT) operating in 660 nm reduce gene expression of inflammatory mediators in the experimental model of collagenase-induced rat tendinitis.RatThe laser irradiation (660 nm, 100 mW, 3 J) used in the treatment of the tendinitis induced by collagenase in Achilles tendon in rats was effective in the reduction of important pro-inflammatory markers such as IL-6 and TNF-α, becoming a promising tool for the treatment of tendon diseases.
Wound healing Pressure ulcer Taradaj2013Evid Based Complement Alternat MedEffect of Laser Irradiation at Different Wavelengths (940, 808, and 658 nm) on Pressure Ulcer Healing: Results from a Clinical Study.Human Placebo-controlledThe laser therapy at a wavelength of 658 nm appeared to be effective at healing pressure ulcers. The wavelengths of 808 and 940 nm did not have any effect in our study.
Skin Laser skin resurfacing wounds / erythema Alster & Wanitphakdeedecha2009Dermatol SurgImprovement of postfractional laser erythema with light-emitting diode photomodulation.Human Split-faceThe LED-treated facial halves were less erythematous in all 20 patients 24 hours postoperatively. The six patients who received the highest mean energy densities during fractional laser treatment continued to exhibit decreased erythema in the LED-treated areas at 48 hours. At 96 hours post-treatment, no discernible differences between facial halves were observed in any patient. Comment: The parameters seem contradictory.
Brain Brain injury Oron2007J NeurotraumaLow-level laser therapy applied transcranially to mice following traumatic brain injury significantly reduces long-term neurological deficits.MouseThe lesion volume of the laser treated mice was significantly lower (1.4%) than the non-treated group (12.1%). Our data suggest that a non-invasive transcranial application of LLLT given 4 h following TBI provides a significant long-term functional neurological benefit.
Muscle Exercise da Silva Alves2014Lasers Med SciAcute effects of low-level laser therapy on physiologic and electromyographic responses to the cardiopulmonary exercise testing in healthy untrained adults.Human RCT/DB CrossoverThe LLLT acutely increases exercise performance in healthy untrained adults probably due to increased O2 extraction by peripheral muscles without causing a significant impact on muscle fatigue.
Wound healing Wounds Ghamsari1997Vet SurgEvaluation of low level laser therapy on primary healing of experimentally induced full thickness teat wounds in dairy cattle.CattleThe LLLT affects various aspects of the healing process, including minimizing inflammation, formation of edema, improvement of skin regeneration and enhancement of collagen synthesis.
Bone Osteoblasts Shin2016Maxillofac Plast Reconstr SurgEffect of low-level laser therapy on bisphosphonate-treated osteoblasts.In vitroThe LLLT does not affect the OPG expression in the hFOB cell line, but it may increase the RANKL and M-CSF expressions, thereby resulting in positive effects on osteoclastogenesis and bone remodeling.
Bone Bone repair Freddo2016J Oral Maxillofac SurgInfluence of a Magnetic Field and Laser Therapy on the Quality of Mandibular Bone During Distraction Osteogenesis in Rabbits.RabbitThe LLLT group exhibited a larger amount of newly formed bone and a larger number of osteoblasts in the cell division phase, but the difference was not statistically relevant compared with the control group.
Muscle Myopathy BupivacainePissulin2017 epubJ Photochem Photobiol BLow-level laser therapy (LLLT) accelerates the sternomastoid muscle regeneration process after myonecrosis due to bupivacaineRatThe LLLT reduced myonecrosis, characterized by a decrease in muscle CK levels, inflammation, necrosis, and atrophy, as well as the number of central nuclei in the muscle fibers and the percentage of collagen. TNFα values remained constant. LLLT, at the dose used, reduced fibrosis and myonecrosis in the sternomastoid muscle triggered by bupivacaine, accelerating the muscle regeneration process.
Hearing Tinnitus Gungor2008J Laryngol OtolEffectiveness of transmeatal low power laser irradiation for chronic tinnitus.Human RCT/DBThe loudness, duration and degree of annoyance of tinnitus were improved, respectively, in up to 48.8, 57.7 and 55.5 per cent of the patients in the active laser group. No significant improvement was observed in the placebo laser group. Jan Tunér: A problem with most studies trying to treat tinnitus with laser light is the lack of proper diagnosis of the patients. Quite a few of these have a somatosensory background (the problem is basicly muscluar). Irradiation into the ear will then have no effect.
Oral Oral mucositis Eduardo2009Photomed Laser SurgSeverity of oral mucositis in patients undergoing hematopoietic cell transplantation and an oral laser phototherapy protocol: a survey of 30 patients.Human Observational / Case seriesThe low grades of OM observed in this survey show the beneficial effects of laser phototherapy, but randomized clinical trials are necessary to confirm these findings.
Muscle Exercise Kakihata2015Einstein (Sao Paulo)Influence of low-level laser therapy on vertical jump in sedentary individuals.HumanThe low intensity laser on the triceps surae, in sedentary individuals, had no significant effects on the variables evaluated.
Pain Shoulder Subacromial impingement syndromeDogan2010Clinics (Sao Paulo)The effectiveness of low laser therapy in subacromial impingement syndrome: a randomized placebo controlled double-blind prospective study.Human RCT/DBThe Low level laser therapy seems to have no superiority over placebo laser therapy in reducing pain severity, range of motion and functional disability.
Nerves PNS Fibular nerve (common)Sene2013Acta Ortop BrasEffects of laser therapy in peripheral nerve regeneration.RatThe low power AsGaAl laser irradiation did not accelerate nerve recovery with any of the doses used.
Oral Oral mucositis Arun Maiya2006Indian J Med ResEffect of low level helium-neon (He-Ne) laser therapy in the prevention & treatment of radiation induced mucositis in head & neck cancer patients.Human RCTThe low-level He-Ne laser therapy during the radiotherapy treatment was found to be effective in preventing and treating the mucositis in head and neck cancer patients.
Brain Brain injury Zhang2014J Cereb Blood Flow MetabLow-level laser therapy effectively prevents secondary brain injury induced by immediate early responsive gene X-1 deficiency.MouseThe low-level laser therapy (LLLT) suppressed proinflammatory cytokine expression like interleukin (IL)-1β and IL-6 but upregulated TNF-α. Moreover, although lack of IEX-1 compromised ATP synthesis, LLLT elevated its production in injured brain. The protective effect of LLLT may be ascribed to enhanced ATP production and selective modulation of proinflammatory mediators. This new closed head injury model provides an excellent tool to investigate the pathogenesis of secondary brain injury as well as the mechanism underlying the beneficial effect of LLLT.
Oral Tooth replantation Matos Fde2016Dent TraumatolEffect of laser photobiomodulation on the periodontal repair process of replanted teeth.RatThe LPBM protocol at λ808 nm and λ660 nm as well as whole milk and soy milk favored the periodontal repair process of replanted teeth in rats.
Oral Orthodontics Root resorptionEkizer2015Lasers Med SciEffect of LED-mediated-photobiomodulation therapy on orthodontic tooth movement and root resorption in rats.RatThe magnitude of movement in the treatment group was higher (1.55 ± 0.33 mm) compared to the control group (1.06 ± 0.35 mm). Histomorphometric analysis of root resorption, expressed as a percentage, showed that the average relative root resorption affecting the maxillary molars on the TM side was 0.098 ± 0.066 in the LPT group and 0.494 ± 0.224 in the control group.
Muscle Exercise Paolillo2014Lasers Surg MedLow-level laser therapy associated with high intensity resistance training on cardiac autonomic control of heart rate and skeletal muscle remodeling in wistar rats.RatThe main results of the present study found that LLLT in conjunction with HIT increased MMP-2 gene expression and some HRV indices. It also appears LLLT has independent positive effects on HRV.
Muscle Myopathy Mdx miceSilva2015Lasers Med SciPre-exercise low-level laser therapy improves performance and levels of oxidative stress markers in mdx mice subjected to muscle fatigue by high-intensity exercise.MouseThe mdx mice treated with LLLT showed significantly lower levels of creatine kinase (CK) and oxidative stress than mdx mice that underwent forced high-intensity exercise on a treadmill. The activities of the antioxidant enzyme superoxide dismutase (SOD) were higher in control mdx mice than in WT mice. LLLT also significantly reduced the level of this marker. LLLT had a beneficial effect also on the skeletal muscle performance of mdx mice.
Wound healing Surgical wounds LCT-1000™ (LiteCure Medical)Karlekar2015Ann Card AnaesthAssessment of feasibility and efficacy of Class IV laser therapy for postoperative pain relief in off-pump coronary artery bypass surgery patients: A pilot study.HumanThe mean (standard deviation [SD]) VRS of all the 100 patients just before application of the first dose of laser was 7.31 (0.94) while on MMT; the same fell to 4.0 (1.279) and 3.40 (2.697) at 1 h and 24 h respectively following first dose of laser. The change of VRS over first 24 h among all the 100 patients was statistically significant (P = 0.000). Laser was re-applied in 40 patients whose VRS was ≥5 (mean [SD] - 6.38 [0.868]) at 24th h. After receiving the 2nd dose of laser the VRS scores fell significantly (P = 0.000) and became 0 at 54th h. No patients required 3rd dose of the laser. No patient required rescue analgesic while on laser therapy.
Wound healing Pressure ulcer Light probe (110)Dehlin2007Aging Clin Exp ResMonochromatic phototherapy: effective treatment for grade II chronic pressure ulcers in elderly patients.Human ControlledThe mean normalized reduction in pressure ulcer size at week 12 was 0.79 for the phototherapy group and 0.50 for the placebo group (95% confidence interval 0.01-0.53; p=0.039). No serious side-effects were noted. Monochromatic pulsating light accelerates healing in grade II pressure ulcers in elderly patients. PDF full text:
Respiratory system Ezzat2016Acta Otorrinolaringol EspUsing low level laser therapy to reduce early postoperative airway obstruction following modified Hogans flap.Human RCT/DBThe mean of the average oxygen saturation was significantly less in the control group in the 1st and 2nd day as compared to the laser group. The need for oxygen and the incidence of OSA in the first 3 days were significantly higher in the control group as compared to the laser group. The degree of edema showed no significant difference in the first day but was significantly higher in the control group in the 2nd and 3rd days. Hence, the need of steroids was significantly higher in the control group in the first 3 days. Comment: Parameters were poorly reported.
Muscle Exercise Wavelength comparisonde Almeida2012Lasers Med SciRed (660 nm) and infrared (830 nm) low-level laser therapy in skeletal muscle fatigue in humans: what is better?Human RCT CrossoverThe mean peak force was significantly greater (p < 0.05) following red (12.14%) and infrared LLLT (14.49%) than following placebo LLLT, and the mean average force was also significantly greater (p < 0.05) following red (13.09%) and infrared LLLT (13.24%) than following placebo LLLT. There were no significant differences in mean average force or mean peak force between red and infrared LLLT. We conclude that both red than infrared LLLT are effective in delaying the development skeletal muscle fatigue and in enhancement of skeletal muscle performance.
Oral Oral mucositis LED phototherapy LED vs LLLTFreitas2014Photomed Laser SurgChemotherapy-induced oral mucositis: effect of LED and laser phototherapy treatment protocols.Human Comparison trialThe mean VAS and WHO scores were significantly smaller in the LED group (p<0.05). However, both groups required the same number of days to reach score zero for mucositis and pain (p>0.05).
Eyes Shmyreva1989Oftalmol Zh[The mechanism of action of laser stimulation of the eye]. [Article in Russian]HumanThe mechanism of action of helium-neon laser stimulation has been studied in 26 eyes of 15 patients with dystrophic diseases of the eye and on the ground of 63 lymphangiographic investigations of the same patients. It was found that low-energy helium-neon laser stimulation (0.05-0.5 mWt/cm2) has a positive effect on restoration of visual functions. Lymphangiographic investigations have revealed a new biological phenomenon--activation of disturbed lymphatic flow under the action of a specially organized laser radiation. The results obtained confirm the earlier hypothesis (M. M. Krasnov et al., 1982) that under the action of laser radiation a normal physiologic system purifying the retina from disintegrated products is engaged into action.
Dermatology Herpes labialis Schindl & Neumann1999J Invest DermatolLow-intensity laser therapy is an effective treatment for recurrent herpes simplex infection. Results from a randomized double-blind placebo-controlled study.Human RCTThe median recurrence-free interval in the laser-treated group was 37.5 wk (range: 2-52 wk) and in the placebo group 3 wk (range: 1-20 wk). This difference was found to be statistically significant (p < 0.0001; Wilcoxons Rank Sum Test). In conclusion, we demonstrated that a total of 10 irradiations with low-intensity laser therapy significantly lowers the incidence of local recurrence of herpes simplex infection.
Dermatology Herpes labialis Dougal & Lee2013Clin Exp DermatolEvaluation of the efficacy of low-level light therapy using 1072 nm infrared light for the treatment of herpes simplex labialis.Human RCTThe median time to healing for the active group was 129 h, compared with 177 h for the control group, which was significant (P = 0.01).
Nerves PNS Nerve injury LED phototherapySerafim2012Lasers Med SciEffects of 940 nm light-emitting diode (led) on sciatic nerve regeneration in rats.RatThe morphological analysis of the nerve indicated that phototherapy can reduce the migration of mononuclear cells to damaged tissue, which reduces areas of edema and fiber degeneration. A 940 nm LED phototherapy source seems to favor the early functional recovery of the injured sciatic nerve.
Nerves Cranial Nerve injury n. facialisAnders1993Lasers Surg MedLow power laser irradiation alters the rate of regeneration of the rat facial nerve.RatThe most effective laser parameters for the low power treatment included daily irradiation with a helium-neon (HeNe) or argon pumped tunable dye laser a wavelength of 633 nm, with a power of 8.5 mW for 90 minutes (45.9 J, 162.4 J/cm2). These data indicate that transcutaneous low power irradiation with the lasers and parameters involved in this study increased the rate of regeneration of rat facial nerve following crush injury.
Nerves PNS Yang & Huang2016J Tissue Eng Regen MedSynergistic effects of low-level laser and mesenchymal stem cells on functional recovery in rats with crushed sciatic nerves.RatThe MSCLLLT group showed a greater recovery in SFI, VA and AA, with significant difference from MSC, LLLT and control groups (p < 0.05). Moreover, markedly enhanced electrophysiological function and expression of S100 immunoreactivity, as well as fewer inflammatory cells and less vacuole formation were also demonstrated after nerve crush injury in the MSCLLLT group when compared with the groups receiving a single treatment (p < 0.05). MSC transplantation combined with LLLT could achieve better results in functional recovery than a conventional treatment of MSC or LLLT alone. LLLT has a synergistic effect in providing greater functional recovery with MSC transplantation after nerve crush injury.
Brain Stroke Lampl2007StrokeInfrared laser therapy for ischemic stroke: a new treatment strategy: results of the NeuroThera Effectiveness and Safety Trial-1 (NEST-1).Human RCT/DB/MSThe NEST-1 study indicates that infrared laser therapy has shown initial safety and effectiveness for the treatment of ischemic stroke in humans when initiated within 24 hours of stroke onset. A larger confirmatory trial to demonstrate safety and effectiveness is warranted. Comment: Despite the positive results, the subsequent NEST-2 and NEST-3 trials could not verify the positive results shown here. Note: A highly cited articly (222 on Google Scholar in 10/2016).
Fertility, genitals, etc. Testicle Toxicity (with high dose) Biphasic dose responseTaha & Valojerdi2004Lasers Surg MedQuantitative and qualitative changes of the seminiferous epithelium induced by Ga. Al. As. (830 nm) laser radiation.RatThe number of germ cells specially the pachytene spermatocytes and elongated spermatids increased after 28.05 J/cm(2) laser radiation. Ultrastructural features of germ and Sertoli cells in this group were similar to that of control; while laser irradiation at 46.80 J/cm(2) had a destructive effect on the seminiferous epithelium such as dissociation of immature spermatids and evident ultrastructural changes in them. Moreover, it was revealed that low doses of laser light have a biostimulatory effect on the spermatogenesis and may provide benefits to the patients with oligospermia and azoospermia.
Muscle Exercise Dos Reis2014Photomed Laser SurgEffects of pre- or post-exercise low-level laser therapy (830 nm) on skeletal muscle fatigue and biochemical markers of recovery in humans: double-blind placebo-controlled trial.Human RCT/DBThe number of repetitions (p=0.8965), RM (p=0.9915), and duration of fatigue (p=0.8424) were similar among the groups. Post-fatigue laser treatment significantly decreased the serum lactate concentration relative to placebo treatment (p<0.01) and also within the group over time (after 5 min vs. after 10 and 15 min, p<0.05 both). The CK level was lower in the post-fatigue laser group (p<0.01).
Penetration Bashkatov2005J Phys D Appl PhysOptical properties of human skin, subcutaneous and mucous tissues in the wavelength range from 400 to 2000 nmThe optical properties of human skin, subcutaneous adipose tissue and human mucosa were measured in the wavelength range 400–2000 nm.
Oral Endodontics Shigetani2011J EndodGaAlAs laser irradiation induces active tertiary dentin formation after pulpal apoptosis and cell proliferation in rat molars.RatThe output energy determined pulpal healing patterns after GaAlAs laser irradiation; the higher energy induced the apoptosis in the affected dental pulp including odontoblasts followed by active cell proliferation in the intense HSP-25-immunoreactive areas surrounding the degenerative tissue, resulting in abundant tertiary dentin formation. Thus, the optimal GaAlAs laser irradiation elicited intentional tertiary dentin formation in the dental pulp. Comment: Some parameters such as energy density or spot size were not reported. Comment: I wonder whether the effect is based on photobiomodulation or heat-stress and hormesis.
Mechanisms Original research Quirk & Whelan2016Photomed Laser SurgEffect of Red-to-Near Infrared Light on the Reaction of Isolated Cytochrome c Oxidase with Cytochrome c.In vitroThe oxidation of cytochrome c by isolated CCO has not been shown to be affected by R-NIR irradiation, whether applied prior to or concurrently with the enzymatic assays. This lack of effect by R-NIR calls into question the CCO activity model of R-NIR photobiomodulation. There could still be a role for CCO in R-NIR-PBM. Although the activity may not be affected, it may be possible that R-NIR reception by CCO in some manner results in increased expression of the same enzyme. It is difficult, however, to envision how such a result could be achieved. Perhaps CCO modulation by R-NIR does not affect the rate of cytochrome c oxidation, but rather increases its efficiency by increasing the proton pumping rate per electron transferred, as argued in a study of isolated rat liver mitochondria. This could improve the production of adenosine triphosphate (ATP), with all of the implied cellular benefits. We have only studied one part of the CCO reaction. In this work, the other substrate, oxygen, is considered to be saturating and not rate limiting. It is possible that the kinetics of the reduction of oxygen by CCO may be affected by R-NIR even if the cytochrome c oxidation may not. It is our intention to study oxygen uptake in a respiration chamber using the Clark electrode technique. Comment: Still, the in vitro setting with isolated CCO, instead of a living cell, could possibly explain these results. Hopefully we get some clarity about the mechanism during the following years.
Joints Meniscus Malliaropoulos2013Lasers Med SciLow-level laser therapy in meniscal pathology: a double-blinded placebo-controlled trial.Human RCT/DBThe pain decreased approximately by 65 % 4 weeks after LLLT and by 22 % in the placebo group. Treatment with LLLT was associated with a significant decrease of symptoms compared to the placebo group: it should be considered in patients with meniscal tears who do not wish to undergo surgery.
Oral Tooth extraction Wisdom toothKazancioglu2014Lasers Med SciComparison of the influence of ozone and laser therapies on pain, swelling, and trismus following impacted third-molar surgery.Human RCTThe pain level and the number of analgesics tablets taken were lower in the ozonated and LLLT applied groups than in the control group. This study showed that ozone and low power laser therapies had a positive effect on the patients quality of life. Trismus in the LLLT group was significantly less than in the ozonated and control groups (p = 0.033). Ozone application showed no superiority in regards of postoperative swelling; however, LLLT group had significantly lower postoperative swelling. Note: There seemed to be no placebo group. A comment was published, noting that this might affect the results.
Fertility, genitals, etc. Dyssmenorrhea Shin2012Arch Gynecol ObstetSkin adhesive low-level light therapy for dysmenorrhoea: a randomized, double-blind, placebo-controlled, pilot trial.Human RCT/DBThe pain reduction rate was 83 % in the active LLLT group, whereas there was only a slight and temporary reduction in pain in the placebo LLLT group. Changes of VAS within 6 months of LLLT showed statistical significance (p = 0.001) over placebo control. In conclusion, this study supported our hypothesis that the direct cause of dysmenorrhoea might not be changes in bioactive substances, such as hormone imbalance, a decrease in serotonin levels or excessive prostaglandin production, but the abnormal function of parts of smooth muscles in the uterus secondary to long-term deficient blood supply into smooth muscle tissue caused by disease or stress. This study also suggests that skin adhesive LLLT administered to acupuncture points might be an effective, simple, safe non-pharmacological method for the treatment of dysmenorrhoea. This study also shows the possibility that even low-level light stimulation on acupuncture points can relax smooth muscles of internal organs through meridians. To the best of our knowledge, this is the first study on the treatment of dysmenorrhoea with skin adhesive LLLT administered to acupuncture points.
Brain Stroke LED phototherapyBoonswang2012BMJ Case RepA new treatment protocol using photobiomodulation and muscle/bone/joint recovery techniques having a dramatic effect on a stroke patients recovery: a new weapon for clinicians.Case reportThe patient in this case report experienced a dramatic recovery/rehabilitation outcome after being treated with the treatment protocol.
Oral Aphthous stomatitis Caputo2012Case Rep MedLaser Therapy of Recurrent Aphthous Ulcer in Patient with HIV Infection.Human Case reportThe patient was treated with laser therapy with the objective to help reverse the damage and decrease the symptoms. After one week there was remission of the lesions. The laser showed to be an important alternative therapy that promoted analgesic, healing effects and improving the quality of life of patients.
Carpal tunnel Carpal tunnel syndrome Elwakil2007Lasers Med SciTreatment of carpal tunnel syndrome by low-level laser versus open carpal tunnel release.HumanThe patients were evaluated clinically and by nerve conduction studies (NCSs) about 6 months after the treatment. LLLT showed overall significant results but at a lower level in relation to surgery. LLLT showed significant outcomes in all parameters of subjective complaints (p < or = 0.01) except for muscle weakness. Moreover, LLLT showed significant results in all parameters of objective findings (p < or = 0.01) except for thenar atrophy. However, NCSs expressed the same statistical significance (p < or = 0.01) after the treatment by both modalities. LLLT has proven to be an effective and noninvasive treatment modality for CTS especially for early and mild-to-moderate cases when pain is the main presenting symptom. Comment: Radiation parameters were insufficiently reported.
Oral Aphthous stomatitis CO2 laserSharon-Buller & Sela2004Oral Surg Oral Med Oral Pathol Oral Radiol EndodCO2-laser treatment of ulcerative lesions.Human Case seriesThe patients, presenting stress-related, chemoradiotherapy-induced, and immuno-related oral aphthosis, reported immediate pain relief and rapid recovery.
Mechanisms Original research HeLa cellsKaru2005Photomed Laser SurgExact action spectra for cellular responses relevant to phototherapy.In vitroThe peak positions are between 613.5 and 623.5 nm (in one spectrum, at 606 nm), in the red maximum. The far-red maximum has exact peak positions between 667.5 and 683.7 nm in different spectra. Two near infrared maxima have peak positions in the range 750.7-772.3 nm and 812.5-846.0 nm, respectively.
Penetration Anders & Wu2016Photomed Laser SurgComparison of Light Penetration of Continuous Wave 810 nm and Superpulsed 904 nm Wavelength Light in Anesthetized Rats.The percentages of light transmission (fluence rate) through muscle and skin were 7.42% (810 nm wavelength) and 4.01% (904 nm wavelength) and through skin were 24.63% (810 nm wavelength) and 19.94% (904 nm wavelength). These data prove that transmission of CW 810 nm wavelength light through muscle and skin and skin alone is greater than transmission of superpulsed 904 nm wavelength light.
Skin Laser skin resurfacing wounds / erythema LED phototherapy (Smartlux, Medmix)Oh2013Dermatol SurgEfficacy of light-emitting diode photomodulation in reducing erythema after fractional carbon dioxide laser resurfacing: a pilot study.Human Split-faceThe postlaser erythema resolved faster on the experimental side than the control side, with improvements noted according to physician assessment and chromometer erythema index. Statistically significant improvements between the two sides were first noted on day 4. Treatment using a 635-nm-wavelength LED array decreases the intensity and duration of post-fractional CO2 laser treatment erythema. Comment: The differences between the groups are quite modest.
Oral Tooth extraction Wisdom toothOliveira Sierra2013TrialsEffect of low-level laser therapy on the post-surgical inflammatory process after third molar removal: study protocol for a double-blind randomized controlled trial.Study protocolThe present study aims to provide a randomized, controlled, double-blind trial to compare four different LLLT parameters in relation to the outcomes of pain, swelling and muscle spasm following surgery for the extraction of impacted third molars and evaluate the effects os surgery on patients quality os life (QOL).
Nerves PNS Nerve regeneration Sural nerveBuchaim2015InjuryEffect of low-level laser therapy (LLLT) on peripheral nerve regeneration using fibrin glue derived from snake venom.RatThe present study demonstrated that the fibrin glue makes axonal regeneration feasible and is an efficient method to recover injured peripheral nerves, and the use of low-level laser therapy enhances nerve regeneration.
Wound healing Burns Yadav2016J Photochem Photobiol BPhotobiomodulatory effects of superpulsed 904nm laser therapy on bioenergetics status in burn wound healing.RatThe present study recapitulated the benefits of LLLT in enhancing CCO activity and ATP synthesis in injured tissue. In addition to this, our results also displayed the role of cellular redox homeostasis in regulation of energy generation. These findings indicated that superpulsed 904 nm LLLT favor aerobic regulation of cellular energy metabolism and a synchronized evasion from the anaerobic glycolysis in burn wound healing. Comment: The huge increase in ATP levels is very interesting. Many other changes were also noted.
Liver Liver regeneration Hepatectomy -> Liver regenerationMelo2005Dig Dis SciEnhancement of liver regeneration by the association of Hyptis pectinata with laser therapy.RatThe present study shows that the association of the aqueous extract of Hyptis pectinata leaves at 200 mg/kg with intraoperative laser therapy can stimulate liver regeneration and cause a reduction in liver mitochondrial respiratory function without altering its phosphorylative activity.
Turtles Skin and shell ulceration Kraut2013Tierarztl Prax Ausg K Kleintiere HeimtiereLaser therapy in a soft-shelled turtle (Pelodiscus sinensis) for the treatment of skin and shell ulceration. A case report.Soft-shelled turtle Case reportThe presented case report describes aetiology including differential diagnoses, diagnostic procedures and therapy of a soft-shelled turtle (Pelodiscus sinensis) suffering from a septicaemic ulcerative dermatitis. Central aspect hereby is the positive curing effect of laser therapy on skin and shell lesions.
Oral Oral surgery Ustaoglu2017 epubPhotomed Laser SurgLow-Level Laser Therapy in Enhancing Wound Healing and Preserving Tissue Thickness at Free Gingival Graft Donor Sites: A Randomized, Controlled Clinical Study.Human RCTThe prevalence of Complete Wound Epithelization was higher in the LLLT group than in the control group on the 14th day (p < 0.001). The bleeding was lower in the test group than in the control group during the first 2 days (p ≤ 0.001). Higher WHI Scores were observed in the test group relative to the control group at all visits (p ≤ 0.001). Color match scores were higher in the test group than in the control group at the first 3 visits (p < 0.05). The TT changed from 4.62 ± 0.79 to 4.71 ± 0.82 mm in the LLLT group and from 4.23 ± 0.62 to 4.01 ± 0.68 mm in the control group. It can be concluded that LLLT enhances FGG donor site wound healing and preserves TT at palatinal donor sites.
Penetration Melanin Brondon2007Photomed Laser SurgMelanin density affects photobiomodulation outcomes in cell culture.In vitroThe Proliferation Index (PI) as measured by CyQuant assay was not statistically different amongst the groups in either cell line. MTT assay results demonstrated a significant dose response effect (p < or = 0.05) in both cell lines with activity inversely proportional to melanin concentration. These results demonstrate that cutaneous melanin content should be taken into consideration in photobiomodulation paradigms. Further studies to quantify these effects are warranted.
Oral Oral mucositis LLLT vs aluminum hydroxideLima2010Braz Dent JEfficacy of low-level laser therapy and aluminum hydroxide in patients with chemotherapy and radiotherapy-induced oral mucositis.Human (not RCT)The prophylactic use of both treatments proposed in this study seems to reduce the incidence of severe OM lesions. However, the LLLT was more effective in delaying the appearance of severe OM.
Muscle Exercise Gomes2014TrialsEfficacy of pre-exercise low-level laser therapy on isokinetic muscle performance in individuals with type 2 diabetes mellitus: study protocol for a randomized controlled trial.Study protocolThe purpose of this randomized clinical trial is to evaluate the efficacy of pre-exercise LLLT on the performance of the quadriceps muscle (peak torque, total muscle work, maximum power and fatigue index - normalized by body mass) in individuals with DM-2. The study will support the practice of evidence-based to the use of LLLT in improving muscle performance in Individuals with DM-2. Data will be published after the study is completed.
Oral Aphthous stomatitis CO2 laserZand2009Lasers Med SciRelieving pain in minor aphthous stomatitis by a single session of non-thermal carbon dioxide laser irradiation.Human RCTThe reduction in pain scores was significantly greater in the laser group than in the placebo group. The procedure itself was not painful, so anesthesia was not required. Powermetry revealed the CO(2) laser power to be 2-5 mW after passing through the gel, which caused no significant temperature rise or any visual effect of damage to the oral mucosa. Our results showed that a low-intensity, non-thermal, single-session of CO(2) laser irradiation reduced pain in miRAS immediately and dramatically, with no visible side effects.
Nerves Diabetic neuropathy Cg2015Laser TherEfficacy of low level laser therapy on painful diabetic peripheral neuropathy.Human ObservationalThe result analysis showed significant reduction in Pain using VAS scale (6.47 ± 0.84 to 1.21 ± 0.78 (p<0.001), MNSI (5.52 ± 1.26 to 2.71 ± 0.97 (reduction in Vibration perception threshold (32.68 ± 6.08 to 24.84 ± 4.29 (<0.001) and a significant increase in the temperature from baseline to post intervention (30.01 ± 2.11 to 31.75 ± 1.03 (p<0. 001). Comment: Parameters were poorly reported. The article had interesting results but wasnt very well written... Comment: The first authors surname might be Kumar instead of Cg.
Bone Bone repair RadiotherapyBatista2014Lasers Med SciEffect of low-level laser therapy on repair of the bone compromised by radiotherapy.RatThe result demonstrated a positive local biostimulative effect of LLLT in normal bone. However, LLLT was not able to revert the bone metabolic damage due to ionizing radiation. Note: The parameters in the abstract seemed to contradict the parameters given in the full text.
Wound healing Wounds Diabetic rats Infection (staph)Ranjbar & Takhtfooladi2016Acta Cir BrasThe effects of photobiomodulation therapy on Staphylococcus aureus infected surgical wounds in diabetic rats. A microbiological, histopathological, and biomechanical study.RatThe result revealed that PBMT resulted in a significant decrease in S. aureus CFU in the PBMT group in comparison to the control group (P<0.05). The length of wounds, in the 2nd and 3rd weeks, in the PBMT group were significantly shorter compared to the control group (P<0.05). PBMT caused a significant increase in the histological parameters in comparison to the control group (P<0.05). Moreover, PBMT significantly increased the breaking strength of the surgical scars produced in the skin of the PBMT group when compared to the control group (P<0.05). Photobiomodulation therapy may be useful in the management of wound infection through a significant bacterial growth inhibition and an acceleration of wound healing process.
Nerves CNS Bells palsy HILT vs LLLTAlayat2014Lasers Med SciEfficacy of high and low level laser therapy in the treatment of Bells palsy: a randomized double blind placebo-controlled trial.Human RCTThe result showed that both HILT and LLLT significantly improved the recovery of patients with Bells palsy. Moreover, HILT was the most effective treatment modality compared to LLLT and massage with exercises.
Oral Pericoronitis Sezer2012Photomed Laser SurgEffects of low-level laser therapy as an adjunct to standard therapy in acute pericoronitis, and its impact on oral health-related quality of life.Human RCTThe results demonstrate that both the 1064-nm Nd:YAG and the 808-nm diode lasers were effective in improving trismus and OHRQoL in acute pericoronitis. Taking into account the limitations of this study, we conclude that the 1064-nm Nd:YAG laser has biostimulatory effects and improves OHRQoL, making it suitable for LLLT. Note: In this study, 660nm didnt have a beneficial effect.
Sinuses Ozturan2015Photomed Laser SurgEffects of Nd:YAG laser irradiation for minimizing edema and pain after sinus lift surgery: randomized controlled clinical trial.Human RCTThe results demonstrate that the 1064 nm Nd:YAG laser was effective in improving OHRQoL and reducing swelling after sinus lift surgery.
Eyes Optic nerve injury (axotomy) LED phototherapyBeirne2016Photochem PhotobiolRed Light Treatment in an Axotomy Model of Neurodegeneration.Ex vivo (mouse)The results demonstrate the ability of 670 nm light to partially prevent ex vivo dendropathy in the mouse retina, suggesting that it is worth exploring as a treatment option for dendropathy-associated neurodegenerative diseases, including glaucoma and Alzheimers disease.
Wound healing Pressure ulcer Shojaei2008Iran J Med Sci (IJMS)Low Level Laser Therapy in the Treatment of Pressure Ulcers in Spinal Cord Handicapped Veterans Living in TehranHumanThe results demonstrated a statistically significant enhancement of the healing process by combination of Low Level Laser with conventional treatments of pressure ulcers.
Dermatology Herpes labialis LED phototherapy vs aciclovirDougal & Kelly2001Clin Exp DermatolA pilot study of treatment of herpes labialis with 1072 nm narrow waveband lightHuman Pilot studyThe results demonstrated that a single 5 min light treatment significantly reduced cold sore healing time by 4 days; 1072 nm light healed cold sores in 4.3 ± 1.8 days (mean ± SD) as compared with acicl