The Mechanisms and Efficacy of Photobiomodulation Therapy for Arthritis: A Comprehensive Review.

Rheumatoid arthritis (RA) and osteoarthritis (OA) have a significant impact on the quality of life of patients around the world, causing significant pain and disability. Furthermore, the drugs used to treat these conditions frequently have side effects that add to the patient's burden. Photobiomodulation (PBM) has emerged as a promising treatment approach in recent years. PBM effectively reduces inflammation by utilizing near-infrared light emitted by lasers or LEDs. In contrast to photothermal effects, PBM causes a photobiological response in cells, which regulates their functional response to light and reduces inflammation. PBM's anti-inflammatory properties and beneficial effects in arthritis treatment have been reported in numerous studies, including animal experiments and clinical trials. PBM's effectiveness in arthritis treatment has been extensively researched in arthritis-specific cells. Despite the positive results of PBM treatment, questions about specific parameters such as wavelength, dose, power density, irradiation time, and treatment site remain. The goal of this comprehensive review is to systematically summarize the mechanisms of PBM in arthritis treatment, the development of animal arthritis models, and the anti-inflammatory and joint function recovery effects seen in these models. The review also goes over the evaluation methods used in clinical trials. Overall, this review provides valuable insights for researchers investigating PBM treatment for arthritis, providing important references for parameters, model techniques, and evaluation methods in future studies.

A Case Series of 11 Horses Diagnosed with Bone Spavin Treated with High Intensity Laser Therapy (HILT).

The aim of this work was to characterize and describe the effect of High Intensity Laser Therapy (HILT) used in the treatment of chronic osteoarthritis in horses. Over a 2 year period, 11 horses with diagnosed bone spavin were treated with HILT as a monotherapy. The horses chosen for this report presented hind limb lameness, were positive in a spavin flexion test and showed improvement after intra-articular anesthesia of the tarsometatarsal joint. Additionally, all the horses presented radiological signs of tarsus osteoarthritis and had not been treated for bone spavin for a minimum of 6 months. Each horse received 10 HILT therapies over 14 days' treatment time with the same laser protocol. At post-treatment orthopedic examination, 4 horses (36%) had improved 2 lameness grades (in the 5 grade American Association of Equine practitioners lameness scale), 4 horses (36%) had improved 1 lameness grade and 3 horses (28%) did not improve. Additionally, 3 horses were totally sound after HILT. Post-treatment spavin test result improvement was observed in 5 horses (45%), and 6 horses (55%) showed the same spavin test grade as before treatment. There were no horses that were sound in the spavin test performed after HILT. Therefore, it seems probable that the application of HILT in horses suffering from bone spavin may decrease joint pain, which influences visual lameness reduction.

Effects of photobiomodulation therapy in chondrocyte response by in vitro experiments and experimental model of osteoarthritis in the knee of rats.

The purpose of this study is to evaluate the effects of photobiomodulation (PBM) therapy in chondrocyte response by in vitro experiments and cartilage repair using an experimental model of osteoarthritis (OA) in the knee of rats. The in vitro experiment was performed with chondrocyte cells, and they were divided into two groups: non-irradiated and irradiated with PBM (808 nm; 0.8 J or 1.4 J). Then, cell proliferation was evaluated after 1, 3, and 5 days. The experimental model of osteoarthritis (OA) was performed in the knee of 64 Wistar rats, and they were assorted into control group (CG), PBM (808 nm; 1.4 J). The results of in vitro showed that PBM 1.4 J increased cell proliferation, on days 1 and 5. However, after 3 days was demonstrated a significant increase in cell proliferation in PBM 0.8 J. The in vivo experiment results demonstrated, on histological analysis, that PBM presented less intense signs of tissue degradation with an initial surface discontinuity at the superficial zone and disorganization of the chondrocytes in the cartilage region when compared to CG, after 4 and 8 weeks. These findings were confirmed by immunohistochemistry and qRT-PCR analysis which showed that PBM increased IL-4, IL-10, COL-2, Aggrecan, and TGF-ß which are anabolic factors and acts on extracellular matrix. Also, PBM reduces the IL1-ß, an inflammatory marker that operates as a catabolic factor on articular cartilage. In conclusion, these results suggest that PBM may have led to a return to tissue homeostasis, promoting chondroprotective effects and stimulating the components of the articular tissue.

Photobiomodulation Therapy Partially Restores Cartilage Integrity and Reduces Chronic Pain Behavior in a Rat Model of Osteoarthritis: Involvement of Spinal Glial Modulation.

OBJECTIVE: Chronic pain associated with osteoarthritis (OA) often leads to reduced function and engagement in activities of daily living. Current pharmacological treatments remain relatively ineffective. This study investigated the efficacy of photobiomodulation therapy (PBMT) on cartilage integrity and central pain biomarkers in adult male Wistar rats. DESIGN: We evaluated the cartilage degradation and spinal cord sensitization using the monoiodoacetate (MIA) model of OA following 2 weeks of delayed PBMT treatment (i.e., 15 days post-MIA). Multiple behavioral tests and knee joint histology were used to assess deficits related to OA. Immunohistochemistry was performed to assess chronic pain sensitization in spinal cord dorsal horn regions. Furthermore, we analyzed the principal components related to pain-like behavior and cartilage integrity. RESULTS: MIA induced chronic pain-like behavior with respective cartilage degradation. PBMT had no effects on overall locomotor activity, but positive effects on weight support (P = 0.001; effect size [ES] = 1.01) and mechanical allodynia (P = 0.032; ES = 0.51). Greater optical densitometry of PBMT-treated cartilage was evident in superficial layers (P = 0.020; ES = 1.34), likely reflecting the increase of proteoglycan and chondrocyte contents. In addition, PBMT effects were associated to decreased contribution of spinal glial cells to pain-like behavior (P = 0.001; ES = 0.38). CONCLUSION: PBMT during the chronic phase of MIA-induced OA promoted cartilage recovery and reduced the progression or maintenance of spinal cord sensitization. Our data suggest a potential role of PBMT in reducing cartilage degradation and long-term central sensitization associated with chronic OA.

Does low level laser therapy has effects on inflammatory biomarkers IL-1ß, IL-6, TNF-α, and MMP-13 in osteoarthritis of rat models-a systemic review and meta-analysis.

Osteoarthritis (OA) is a chronic degenerative joint disease and is considered as the most common cause of pain and disability. To the best of our knowledge, it is generally observed that there is a lack of evidence on the effects of low-level laser therapy (LLLT) on inflammatory cytokines in OA. The present review aims to appraise the current evidence of efffects of LLLT on inflammatory cytokines in OA of the knee. Medical databases such as Medline, PubMed, EMBASE, PEDro CINAHL, Web of Science, Cochrane register, and Google reference were searched from its inception to June 2019. Articles that meet the inclusion criteria: subjects (animals-Wistar rats) induced with OA; rats with age group of 50-90 days; weight of 150-300 g; finding the effects of LLLT; reporting inflammatory cytokines; and articles written in English were included. The reviewers assessed the methodological quality of the primary studies. Data of inflammatory cytokines IL-1ß, IL-6, TNF-α, and MMP-13 were extracted for analysis. The Q (x2) test and I2 statistics analysis were performed to find the heterogeneity evaluation. Standard mean difference (SMD) and its 95% confidence interval (CI) were used to synthesize the data. Two hundred eleven potential articles were identified and 186 articles were excluded based on the selection criteria. The rest of the 25 articles were read and 8 articles were selected for further study. From the study, it is observed that the laser therapy group had mild to moderate improvement than control group in IL-1ß, TNF-α, and MMP-13 (IL-1ß; SMD 1.21 [95% CI - 0.278, 2.704], TNF-α; SMD 5.19 [95% CI 2.413, 7.961], and MMP-13 SMD - 1.45 [95% CI - 5.121, 2.211]), while IL-6 [SMD 3.11 (95% CI 0.662, 5.549] did not show any considerable improvement after laser therapy. The present review provides the evidence of LLLT-dependent reduction of IL-1ß, TNF-α, and MMP-13, and its ability to modulate proliferation of inflammatory cells, which makes LLLT a suitable treatment for OA. Though the included studies showed a high heterogeneity in treatment parameter, the beneficial effect of LLLT on changes in inflammatory cytokines, such as IL-6, seems to be unaffected.

Effects of arthrocentesis and low-level laser therapy on patients with osteoarthritis of the temporomandibular joint.

This retrospective study examined whether arthrocentesis combined with 10 sessions of low-level laser therapy (LLLT) improved the clinical outcomes of patients with temporomandibular joint osteoarthritis (TMJ-OA) compared with arthrocentesis alone. Data from two groups of patients (total: n=36) with unilateral TMJ-OA were evaluated. The groups were established according to their treatment regimens: Group 1 (arthrocentesis alone; n=19) and Group 2 (arthrocentesis plus LLLT; n=17). All patients had been diagnosed in accordance with the Research Diagnostic Criteria for Temporomandibular Joint Disorders (RDC/TMD) (Axis I Group IIIb) protocol. They all underwent the same arthrocentesis protocol, but those in Group 2 also received 10 sessions of LLLT immediately afterwards. The outcome variables were the visual analogue scale scores (VAS 1, VAS 2) for various treatment outcomes and millimetric measurements of mandibular movements over both the short and long term. Intra-group comparisons showed significant short and long-term improvements for both groups, but outcomes were better over the long term than the short term in both. In addition, greater improvements in muscle palpation scores and mandibular movements were achieved in Group 2 than in Group 1. In conclusion, although both techniques improved joint pain and function, a combination with LLLT seemed to have an additional benefit for myofascial components.

Preliminary clinical experience of low-level laser therapy for the treatment of canine osteoarthritis-associated pain: A retrospective investigation on 17 dogs.

Background: Osteoarthritis (OA) is common in dogs and causes chronic pain that affects the quality of life and may not respond to analgesics. Objective: The objective of this study was to determine whether low-level laser therapy (LLLT) would improve the quality of life and help reducing systemic analgesics, in dogs with OA. Methods: Seventeen client-owned dogs diagnosed with OA and associated pain were included. The diagnosis of OA was confirmed by orthopedic and radiographic examination. Pain was evaluated in each dog with the canine brief pain inventory (CBPI), compiled by the dog owners, as well as with a visual analog scale (VAS) and the colorado state canine chronic pain scale, used by the clinician. The LLLT was performed weekly in each study dog, for a total period of 6 weeks. The CBPI was then repeated at 2, 4, 6, and 8 weeks after the first laser session, whereas the VAS was reassessed at weeks 2 and 6. The dogs were observed for the occurrence of laser-related side effects. Results: Both CBPI and VAS were significantly reduced after the first laser session (9.2 ± 3.8 and 5.2 ± 1.1, respectively) compared to pretreatment values (11.8 ± 3.6 and 7.6 ± 0.9, respectively; and p = 0.018 and p < 0.001, respectively) and continued to decrease over time until the end of the therapy. Based on these results and improved function, as assessed by the orthopedic surgeon, the pharmacological analgesic therapy was reduced by the clinician at week 2 in 13 of 17 dogs. Laser-related side effects were not observed. Conclusion: This retrospective report provides a basis for future investigations, needed to clarify whether laser therapy may be beneficial to treat canine OA-associated pain. The preliminary findings are promising and suggest that LLLT may help reducing the analgesic administration and improving client satisfaction and the quality of life of dogs with OA.

Extracorporeal Shock Wave Therapy for the Treatment of Osteoarthritis: A Systematic Review and Meta-Analysis.

BACKGROUND: Osteoarthritis is the most common musculoskeletal disease. Extracorporeal shockwave therapy had shown an effect on osteoarthritis in both some animal experiments and clinical studies, but there was no systematic review to confirm the value of shockwave therapy in the treatment of all types of osteoarthritis and compare it with other traditional therapies (especially traditional Chinese medicine). METHOD: PubMed, Medline, the Cochrane Central Register of Controlled Trials, Web of Science, Chinese National Knowledge Infrastructure, WANFANG database, and VIP database were searched up to December 10, 2019, to identify randomized controlled trials comparing shockwave therapy and other treatments for osteoarthritis. Visual analogue scale and the Western Ontario and McMaster Universities Osteoarthritis Index were extracted and analyzed by RevMan and STATA software as outcomes of pain reduction and functional improvement. Adverse reactions were recorded to evaluate the safety of shockwave therapy. RESULTS: Shockwave therapy had significant improvement in both pain reduction and functional improvement compared with placebo, corticosteroid, hyaluronic acid, medication, and ultrasound (P < 0.05). In functional improvement, shockwave therapy showed statistical improvement compared with kinesiotherapy and moxibustion (P < 0.05) but not with acupotomy surgery (P = 0.24). A significant difference between shockwave therapy and platelet-rich plasma was observed in pain reduction (P < 0.05) but not in functional improvement (P = 0.89). Meanwhile, a statistical difference was found between shockwave therapy and fumigation in functional improvement (P < 0.05) but not in pain reduction (P = 0.26). Additionally, there was no statistically significant difference between shockwave therapy and manipulation in both pain reduction (P = 0.21) and functional improvement (P = 0.45). No serious adverse reaction occurred in all of studies. CONCLUSIONS: Extracorporeal shockwave therapy could be recommended in the treatment of osteoarthritis as a noninvasive therapy with safety and effectiveness, but the grade of recommendations needs to be discussed in a further study.

Applications of Photobiomodulation Therapy to Musculoskeletal Disorders and Osteoarthritis with Particular Relevance to Canada.

Background: Musculoskeletal disorders caused by osteoarthritis (MSDs/OA) are a growing problem in the modern industrialized society in Canada. Overall aging of the general population and a progressive lack of exercise contribute to this alarming increase. Moreover, a range of chronic conditions including cardiovascular and mental diseases show significantly higher comorbidity with MSDs/OA. Conventional medical treatment for MSDs/OA includes nonsteroidal anti-inflammatory drugs and opiate pain killers. These drugs have major drawbacks such as a relative lack of efficacy, potential for addiction, and even death (Vioxx scandal). Photobiomodulation (PBM) was discovered over 50 years ago but has still not attained widespread acceptance by the medical community. This is partly due to uncertainty about the precise molecular mechanisms of action and a bewildering array of different wavelengths and dosimetric parameters employed in reported studies. Objective: The goal of this review was to survey literature reports of PBM, also known as low-level laser therapy used for treatment of MSDs/OA, concentrating on the growth over time, different wavelengths employed, and application to different joints. Methods: We searched the PubMed database for publication of study on PBM to treat the most common joints. Results: We show that the field of PBM to treat MSDs/OA is expanding exponentially over the past 20 years. A trend has emerged over time for more power to achieve better effective treatments, and the understanding of the physiological effect of safe parameters has improved. There is, however, no consensus on the best set of parameters to treat a specific patient indication. Conclusions: Finally, we highlight gaps in our knowledge and the barriers to further clinical trials. We suggest that the growing body of evidence indicating efficacy, and the almost total lack of side effects, should encourage continued clinical research to support clinical applications where better rehabilitation treatments are much needed.

Short term histopathological effects of GaAlAs laser on experimentally induced TMJ osteoarthritis in rabbits.

The aim of this study was to evaluate the biostimulation (BS) effect of the gallium-aluminum-arsenide (GaAlAs) diode laser by histopathology with an experimental osteoarthritis (OA) model in the temporomandibular joints (TMJ) of rabbits, in the early period. GaAlAs diode laser is used for pain reduction in TMJ disorders. Twenty-four adult male New Zealand white rabbits were randomly divided into three equal groups: Control Group (CG), Study Group 1 (SG-1), and Study Group 2 (SG-2). Mono-iodoacetate (MIA) was administered to the right TMJs of all rabbits. The rabbits did not undergo any treatment for four weeks to allow the development of osteoarthritis. In SG-1, laser BS was applied to the rabbits at 940 nm, 5 W, and 15 J/cm2 in continuous wave mode at 48-hour intervals for 14 sessions; and in SG-2, laser BS was applied with the same parameters at 24-hour intervals for 28 sessions. Laser BS was not applied to the rabbits in CG. All rabbits were sacrificed simultaneously. The TMJ cartilage, osteochondral junction, chondrocyte appearance, and subchondral ossification were evaluated histopathologically. There was no statistically significant difference between the groups in terms of cartilage, osteochondral junction, chondrocyte appearance, and subchondral ossification values (p > 0.05). The laser BS protocol used in the study had no positive histopathological effects on TMJ OA in the early period.

Interleukin-10 and collagen type II immunoexpression are modulated by photobiomodulation associated to aerobic and aquatic exercises in an experimental model of osteoarthritis.

The aim of this study was to compare the effects of photobiomodulation (PBM) associated with an aerobic and an aquatic exercise training on the degenerative process related to osteoarthritis (OA) in the articular cartilage in rats. Fifty male Wistar rats were randomly divided into 5 groups: OA control group (CG), OA plus aerobic training group (AET), OA plus aquatic training group (AQT), OA plus aerobic training associated with PBM group (AETL), OA plus aquatic training associated with PBM group (AQTL). The aerobic training (treadmill; 16 m/min; 50 min/day) and the aquatic training (water jumping; 50-80% of their body mass) started 4 weeks after the surgery and they were performed 3 days/week for 8 weeks. Moreover, PBM was performed after the physical exercise trainings on the left joint. Morphological characteristics and immunoexpression of IL-10, TGF-ß, and collagen type I (Col I) and II (Col II) of the articular cartilage were evaluated. The results showed that all the treated groups (exercise and PBM) presented less intense signs of degradation (measured by histopathological analysis and OARSI grade system). Additionally, aerobic and aquatic exercise training rats (associated or not with PBM) showed increased IL-10 (AET p = 0.0452; AETL p = 0.03; AQTL p = 0.0193) and Col II (AET p = 0.012; AQT p = 0.0437; AETL p = 0.0001; AQTL p = 0.0001) protein expression compared to CG. Furthermore, a statistically higher TGF-ß expression was observed in AET (p = 0.0084) and AETL (p = 0.0076) compared to CG. These results suggest that PBM associated with aerobic and aquatic exercise training were effective in mediating chondroprotective effects and maintaining the integrity of the articular tissue in the knees of OA rats.

Can photobiomodulation associated with implantation of mesenchymal adipose-derived stem cells attenuate the expression of MMPs and decrease degradation of type II collagen in an experimental model of osteoarthritis?

This study aimed to determine whether photobiomodulation therapy (PBMT) could improve the bioavailability and chondroprotective benefits of mesenchymal stem cells injected into the knees of rats used as an experimental model of osteoarthritis (OA) as well as reduce the expression of matrix metalloproteinases (MMPs) and degradation of type II collagen (COL2-1) in the cartilage. Adipose-derived stem/stromal cells (ADSCs) were collected from three male Fischer 344 rats and characterized by flow cytometry. Fifty female Fischer 344 rats were distributed into five groups of 10 animals each. These groups were as follows: control, OA, OA PBMT, OA ADSC, and OA ADSC PBMT. OA was induced in the animals using a 4% papain solution. Animals from the OA ADSC and OA ADSC PBMT groups received an intra-articular injection of 10 × 106 ADSCs and were treated with PBMT by irradiation (wavelength: 808 nm, power: 50 mW, energy: 42 J, energy density: 71.2 J/cm2, spot size: 0.028). Euthanasia was performed 7 days after the first treatment. The use of PBMT alone and the injection of ADSCs resulted in downregulation of pro-inflammatory cytokines and MPs in cartilage compared to the OA group. PBMT and ADSCs caused upregulation of tissue inhibitors of MPs 1 and 2 and mRNA and protein expression of COL2-1 in cartilage compared to the OA group. The intra-articular injection of ADSCs and PBMT prevented joint degeneration resulting from COL2-1 degradation and modulated inflammation by downregulating cytokines and MMPs in the OA group.

Chondroitin sulfate and glucosamine sulfate associated to photobiomodulation prevents degenerative morphological changes in an experimental model of osteoarthritis in rats.

The aim of this study was to compare the effects of combined treatment with chondroitin sulfate and glucosamine sulfate (CS/Gl) and photobiomodulation (PBM) on the degenerative process related to osteoarthritis (OA) in the articular cartilage in rats. Forty male Wistar rats were randomly divided into four groups: OA control group (CG); OA animals submitted to PBM treatment (PBM); OA animals submitted to CS/Gl treatment (CS/Gl); OA submitted to CS/GS associated with PBM treatments (GS/Gl + PBM). The CS/Gl started 48 h after the surgery, and they were performed for 29 consecutive days. Moreover, PBM was performed after the CS/Gl administration on the left joint. Morphological characteristics and immunoexpression of interleukin 10 (IL-10) and 1 beta (IL-1ß) and collagen type II (Col II) of the articular cartilage were evaluated. The results showed that all treated groups (CS/Gl and PBM) presented attenuation signs of degenerative process (measured by histopathological analysis) and lower density chondrocytes [PBM (p = 0.0017); CS/Gl (p = 0.0153) and CS/Gl + PBM (p = 0.002)]. Additionally, CS/Gl [associated (p = 0.0089) or not with PBM (p = 0.0059)] showed significative lower values for OARSI grade evaluation. Furthermore, CS/GS + PBM decreased IL-1ß protein expression (p = 0.0359) and increased IL-10 (p = 0.028) and Col II imunoexpression (p = 0.0204) compared to CG. This study showed that CS/Gl associated with PBM was effective in modulating inflammatory process and preventing the articular tissue degradation in the knees OA rats.

Review of Literature on Low-level Laser Therapy Benefits for Nonpharmacological Pain Control in Chronic Pain and Osteoarthritis.

Introduction: Low-level laser therapy (LLLT) is a form of light therapy that triggers biochemical changes within cells. Photons are absorbed by cellular photoreceptors, triggering chemical alterations and potential biochemical benefits to the human body. LLLT has been used in pain management for years and is also known as cold laser therapy, which uses low-frequency continuous laser of typically 600 to 1000 nm wavelength for pain reduction and healing stimulation. Many studies have demonstrated analgesic and anti-inflammatory effects provided by photobiomodulation in both experimental and clinical trials. Objective: The purpose of this research article was to present a summary of the possible pain management benefits of LLLT. Results: In cold laser therapy, coherent light of wavelength 600 to 1000 nm is applied to an area of concern with hope for photo-stimulating the tissues in a way that promotes and accelerates healing. This is evidenced by the similarity in absorption spectra between oxidized cytochrome c oxidase and action spectra from biological responses to light. LLLT, using the properties of coherent light, has been seen to produce pain relief and fibroblastic regeneration in clinical trials and laboratory experiments. LLLT has also been seen to significantly reduce pain in the acute setting; it is proposed that LLLT is able to reduce pain by lowering the level of biochemical markers and oxidative stress, and the formation of edema and hemorrhage. Many studies have demonstrated analgesic and anti-inflammatory effects provided by photobiomodulation in both experimental and clinical trials. Conclusion: Based on current research, the utilization of LLLT for pain management and osteoarthritic conditions may be a complementary strategy used in clinical practice to provide symptom management for patients suffering from osteoarthritis and chronic pain.

Comparative evaluation of the early effects of the low-level laser therapy versus intra-articular steroids on temporomandibular joint acute osteoarthritis in rats: A histochemical, molecular and imaging evaluation.

BACKGROUND: Osteoarthritis (OA) is a serious degenerative joint disease. It is one of the main causes of disability in the world. Current treatment modalities have numerous side effects. Subsequently, health experts are looking for alternative therapies. OBJECTIVES: The aim of the study was to evaluate the early effects of low-level laser therapy (LLLT) vs intraarticular (IA) corticosteroids (CS) on acute temporomandibular joint osteoarthritis (TMJOA). MATERIAL AND METHODS: Sixty rats were divided into 3 groups: group 1- untreated OA; group 2 - OA treated with CS; and group 3 - OA treated with LLL. Half of the animals in each group were sacrificed at 1 and 4 weeks post treatment. The temporomandibular joint was dissected and evaluated histochemically, using quantitative real-time polymerase chain reaction (qRT-PCR), and radiographically. RESULTS: Histochemically, Safranin-O staining revealed an obvious reduction in proteoglycans in the untreated osteoarthritic group. However, both of the treated groups showed a moderate increase in glycosaminoglycan (GAG) staining. As for the qRT-PCR results, caspase-3 showed the highest mean value in the untreated OA group, followed by the CS group, while the lowest mean value was recorded in the LLL group. Radiographically, the condyle showed erosion, flattening, osteophyte formation, and sclerosis in the untreated group, but there was great improvement in both of the treated groups. CONCLUSIONS: Both laser and cortisone showed reparative and formative effects, as evidenced by the increases in the proteoglycan content. However, LLL was superior in its anti-apoptotic effects. Cone beam computed tomography (CBCT) is a valuable tool in assessing osseous abnormalities.

Short term histopathological effects of GaAlAs laser on experimentally induced TMJ osteoarthritis in rabbits

Abstract The aim of this study was to evaluate the biostimulation (BS) effect of the gallium-aluminum-arsenide (GaAlAs) diode laser by histopathology with an experimental osteoarthritis (OA) model in the temporomandibular joints (TMJ) of rabbits, in the early period. GaAlAs diode laser is used for pain reduction in TMJ disorders. Twenty-four adult male New Zealand white rabbits were randomly divided into three equal groups: Control Group (CG), Study Group 1 (SG-1), and Study Group 2 (SG-2). Mono-iodoacetate (MIA) was administered to the right TMJs of all rabbits. The rabbits did not undergo any treatment for four weeks to allow the development of osteoarthritis. In SG-1, laser BS was applied to the rabbits at 940 nm, 5 W, and 15 J/cm2 in continuous wave mode at 48-hour intervals for 14 sessions; and in SG-2, laser BS was applied with the same parameters at 24-hour intervals for 28 sessions. Laser BS was not applied to the rabbits in CG. All rabbits were sacrificed simultaneously. The TMJ cartilage, osteochondral junction, chondrocyte appearance, and subchondral ossification were evaluated histopathologically. There was no statistically significant difference between the groups in terms of cartilage, osteochondral junction, chondrocyte appearance, and subchondral ossification values (p > 0.05). The laser BS protocol used in the study had no positive histopathological effects on TMJ OA in the early period.

[Low level laser therapy : A narrative literature review on the efficacy in the treatment of rheumatic orthopaedic conditions]. / Low-Level-Lasertherapie : Eine narrative Literaturübersicht zur Wirksamkeit bei der Behandlung rheumatologisch-orthopädischer Krankheitsbilder.

BACKGROUND: In low level laser therapy (LLLT) low wattage lasers are used to irradiate the affected skin areas, joints, nerves, muscles and tendons without any sensation or thermal damage. Although the exact mechanism of its effect is still unknown, it seems beyond dispute that LLLT induces a variety of stimulating processes at the cellular level affecting cell repair mechanisms, the vascular system and lymphatic system. LLLT has been popular among orthopaedic practitioners for many years, whereas university medicine has remained rather sceptical about it. OBJECTIVES: Overview of studies on the efficacy of LLLT in the treatment of rheumatic orthopaedic conditions, i. e. muscle, tendon lesions and arthropathies. MATERIALS AND METHODS: Narrative literature review (PubMed, Web of Science). RESULTS: While earlier studies often failed to demonstrate the efficacy of LLLT, several recent studies of increasing quality proved the efficacy of LLLT in the treatment of multiple musculoskeletal pain syndromes like neck or lower back pain, tendinopathies (especially of the Achilles tendon) and epicondylolpathies, chronic inflammatory joint disorders like rheumatoid arthritis or chronic degenerative osteoarthritis of the large and small joints. In addition, there is recent evidence that LLLT can have a preventive capacity and can enhance muscle strength and accelerate muscle regeneration. CONCLUSION: LLLT shows potential as an effective, noninvasive, safe and cost-efficient means to treat and prevent a variety of acute and chronic musculoskeletal conditions. Further randomized controlled studies, however, are required to confirm this positive assessment.

Photobiomodulation therapy in the modulation of inflammatory mediators and bradykinin receptors in an experimental model of acute osteoarthritis.

The objective of this study was to evaluate the effects of photobiomodulation therapy (PBMT) on inflammatory indicators, i.e., inflammatory mediators (TNF-α and CINC-1), and pain characterized by hyperalgesia and B1 and B2 receptor activation at 6, 24, and 48 h after papain-induced osteoarthritis (OA) in rats. Fifty-four rats were subjected to hyperalgesia evaluations and then divided randomly into three groups-a control group and two groups OA and OA PBMT group by using laser parameters at wavelength (808 nm), output power (50 mW), energy per point (4 Joules), power density (1.78 W/cm2), laser beam (0.028 cm2), and energy density (144 J/cm2)-the induction of osteoarthritis was then performed with 20-µl injections of a 4 % papain solution dissolved in 10 µl of saline solution, to which 10 µl of cysteine solution (0.03 M). The statistical analysis was performed using two-way ANOVA with Bonferroni's post hoc test for comparisons between the 6, 24, and 48 h and team points within each group, and between the control, injury, and PBMT groups, and p < 0.05 was considered to indicate a significant difference. The hyperalgesia was evaluated at 6, 24, and 48 h after the injury. PBMT at a wavelength of 808 nm and doses of 4 J, administered afterward, promotes increase at the threshold of pressure stimulus at 6, 24, and 48 h after application and promote cytokine attenuation levels (TNF and CINC-1) and bradykinin receptor (B1 and B2) along the experimental period. We conclude that photobiomodulation therapy was able to promote the reduction of proinflammatory cytokines such as TNF-α and CINC-1, to reduce the gene and protein expression of the bradykinin receptor (B1 and B2), as well as increasing the stimulus response threshold of pressure in an experimental model of acute osteoarthritis.

Effectiveness of an aquatic exercise program and low-level laser therapy on articular cartilage in an experimental model of osteoarthritis in rats.

OBJECTIVE: The aim of this study was to evaluate the effects of an aquatic exercise program and low-level laser therapy (LLLT) (associated or not) on degenerative modifications and inflammatory mediators on the articular cartilage using an experimental model of knee OA. METHOD: Forty male Wistar rats were divided into 4 groups: knee OA - without treatment (OA); OA plus exercise program group (OAE); OA plus LLLT (OAL); OA plus exercise program associated with LLLT (OAEL). Trained rats performed a water-jumping program carrying a load equivalent to 50-80 % of their body mass strapped to their chest. The laser irradiation was used either as the only method or after the exercise training had been performed, at 2 points contact mode (medial and lateral side of the left joint). The treatments started 4 weeks after the surgery, 3 days/week for 8 weeks. RESULTS: The results revealed that all treated groups (irradiated or not) exhibited a better pattern of tissue organization, with less fibrillation and irregularities along the articular surface and improved chondrocytes organization. Also, a lower cellular density and structural damage (OARSI score) and higher thickness values were observed in all treated groups. Additionally, OAE and OAEL showed a reduced expression in IL-1ß and caspase-3 as compared with OA. Furthermore, a statistically lower MMP-13 expression was only observed in OAEL as compared with OA. CONCLUSION: These results suggest that aquatic exercise program and LLLT were effective in preventing cartilage degeneration. Also, physical exercise program presented anti-inflammatory effects in the knees in OA rats.

Positive effects of low level laser therapy (LLLT) on Bouchard's and Heberden's osteoarthritis.

BACKGROUND AND OBJECTIVE: Osteoarthritis (OA) is a common chronic disorder. While research usually focuses on OA of the large joints, OA of the hand receives relatively little attention resulting in a lack of a therapeutic gold standard. Low level laser therapy (LLLT)/photobiomodulation therapy has been successfully used to treat a variety of medical conditions. Nevertheless, its merits in the treatment of (hand) OA remain controversial. The aim of the present study was to examine the longitudinal effect of LLLT on the three major hand OA symptoms-pain, swelling, reduced joint mobility-in patients suffering from Bouchard's and Heberden's OA. STUDY DESIGN/MATERIALS AND METHODS: Thirty-four patients (32 females) aged 61.21 ± 2.13 years were administered 5-10 LLLT sessions to 85 joints (47 proximal and 38 distal interphalangeal joints). Therapy took place twice a week. Pain (Visual Analogue Scale), ring size (perimeter in mm), and range of motion (extension/flexion) were measured at baseline and after five treatments for all patients, and additionally after seven sessions and 8 weeks after treatment ended for patients who received more than five and seven treatments, respectively. Eighteen patients (37 joints) received only five treatments, 10 patients (29 joints) were administered seven treatments, and six patients (19 joints) were administered 10 LLLT sessions. RESULTS: LLLT significantly reduced pain and ring size and increased range of motion after five and seven treatments (all P's < 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. CONCLUSIONS: LLLT is a safe, non-invasive, efficient and efficacious means to reduce pain and swelling and to increase joint mobility in patients suffering from Heberden's and Bourchard's OA. Further randomized controlled studies are needed to examine medium- to long-term effects as well as the ideal LLLT parameters. Lasers Surg. Med. 48:498-504, 2016. © 2016 Wiley Periodicals, Inc.