Photobiomodulation of Pain and Inflammation in Microcrystalline Arthropathies: Experimental and Clinical Results

Recent advances in the therapeutic management of calcium pyrophosphate deposition disease

Calcium pyrophosphate deposition (CPPD) disease is a form of crystal-induced arthropathy that arises from the accumulation of calcium pyrophosphate crystals within joints and soft tissues. This process leads to inflammation and damage to the affected joints. It can present asymptomatically or as acute or chronic inflammatory arthritis. Risk factors and comorbidities, including prior joint injury, osteoarthritis, hereditary or familial predisposition, and metabolic diseases, should be evaluated in CPPD cases. The management of CPPD remains a challenge in the sparsity of randomized controlled trials. The lack of such trials makes it difficult to establish evidence-based treatment protocols for CPPD. This review provides an overview of the current pharmacological management of CPPD, focusing on reducing inflammation, alleviating symptoms, and preventing acute flares. Non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and colchicine are effective in managing acute CPP arthritis. Colchicine may also be used prophylactically to prevent recurrent flares. In cases where other treatments have failed, anakinra, an interleukin-1 receptor antagonist, can be administered to alleviate acute flares. The management of chronic CPP inflammatory arthritis includes NSAIDs and/or colchicine, followed by hydroxychloroquine, low-dose glucocorticoids, and methotrexate, with limited data on efficacy. Tocilizumab can be used in refractory cases. In small studies, synovial destruction using intra-articular injection of yttrium 90 can decrease pain. To date, no disease-modifying therapies exist that reduce articular calcification in CPPD.

Er:YAG Laser Therapy on Alveolar Osteitis After Mandibular Third Molar Surgery: A Randomized Controlled Clinical Study

Background: Alveolar osteitis (AO) or "dry socket" affects the quality of life of patients, and there is a high clinical demand for its effective treatment. Objective: To evaluate the effect of Er:YAG laser therapy (ErLT) on AO after mandibular third molar surgery. Methods: Eighty-three patients were randomly divided into Er (n = 43) and control groups (n = 40). In the Er group, the Er:YAG laser (2940 nm; AT Fidelis Fotona, Ljubljana, Slovenia) was used to irradiate the AO site directly in micro short-pulsed mode (pulse duration 0.1 ms, pulse energy 100 mJ, frequency 40 Hz, water 4, and air 2) until all debris and necrotic material had been removed, exposing fresh bone and soft tissue surfaces with blood exudation. The control group received mechanical therapy until the treated lesions resembled those in the Er group. Pain assessment was performed at baseline and on days 1-7 post-intervention using the visual analog scale (VAS). Wound healing was assessed using the wound healing index (WHI). The operating times of the two therapies were also recorded. Results: Group Er had lower VAS scores than the control group on days 1-3 (p = 0.00). There was no significant difference between the two groups on days 4-7 (p = 0.15). The WHI scores were better in the Er group than those in the control group (t = 2.65, p = 0.01), especially in terms of redness (t = 2.70, p = 0.01). There was no significant difference in the operating time between the two groups (t = 0.76, p = 0.45). Conclusions: Compared with mechanical therapy, ErLT for AO provides rapid pain relief and improved wound healing.

Regenerative Therapies for Basal Thumb Arthritis-A Systematic Review

Basal thumb arthritis is a painful and debilitating pathology that can severely reduce a patients' quality of life. Common therapies include oral pain control, local steroid injections and/or surgery. Yet, therapeutic data on long-term improvement and even cartilage repair are scarce. This review aims to present the currently available literature on novel therapies for basal thumb arthritis, including platelet-rich plasma (PRP), fat grafting and phototherapy, and investigate their potential efficacy. The entire OVID database and PubMed were searched for studies containing the topics PRP injection, lipofilling, laser treatment and regenerative treatment for carpometacarpal arthritis. Seven studies on the effect of fat tissue on basal thumb arthritis were found. Four authors reported on PRP injections, one RCT examined a combinational treatment of PRP and fat grafting, another phototherapy for the thumb joint and one prospective trial on chondrocyte transplantation was found. Pain improvement and decreased impairment were reported in the majority of PRP and/or fat grafting studies as well as after chondrocyte implantation. Phototherapy did not significantly improve the condition. This review revealed that only limited data on regenerative therapies for carpometacarpal arthritis are currently available, yet PRP and lipofilling show promising results and merit further investigation.

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.

Acute effects of photobiomodulation applied on the dorsal root ganglion in gout model-induced rats

Gouty arthritis is an inflammatory disease that triggers symptoms such as pain, swelling, and joint stiffness. Since its main therapy is medication, research on other forms of treatment that do not generate side effects is necessary. Given this, the objective of this research was to evaluate the effects of combined photobiomodulation (LASER and LED) applied on the dorsal root ganglion (DRG) in an experimental model of gouty arthritis. For this, 40 Wistar rats were randomized into 4 groups: simulation of the model with saline injection, without treatment (CTL; n = 10); gout simulation with photobiomodulation treatment (CTL-PBM; n = 10); gout model with the injection of monosodium urate crystals (1.25 mg) in the femorotibial joint, without treatment (GOT; n = 10); or gout model with photobiomodulation treatment (GOT-PBM; n = 10). After 7 h of gout induction, photobiomodulation was performed with a cluster of 4 diodes applied to the GRD region in animals from the CTL-PBM and GOT-PBM groups. After analysing the results, it was concluded that the therapy favored the reduction of edema and joint incapacity, as well as the increase in the nociceptive threshold and plantar grip strength. Furthermore, PBM stimulated an increase in the inflammatory response (with increased levels of IL-1β and greater recruitment of leukocytes) and greater activation of the antioxidant system. Therefore, PBM can be considered an effective therapeutic alternative to improve the functional status in this model of joint disease.

Calcium pyrophosphate deposition (CPPD) disease - Treatment options

In contrast to gout, no disease-modifying therapies currently exist that reduce articular crystal deposition of calcium pyrophosphate crystals (CPPs). Treatment is aimed at ameliorating the inflammatory response and reducing the frequency and severity of clinical symptoms due to CPP deposition (CPPD). Despite being one of the most common forms of inflammatory arthritis, CPPD remains under-studied and evidence-based treatment guidelines remain lacking. Commonly used treatments for clinical manifestations of CPPD (non-steroidal anti-inflammatory drugs [NSAIDs], colchicine and corticosteroids [CSs]) are extrapolated from use in gout. Anakinra and tocilizumab can be used in refractory cases. Though no current crystal-targeted treatments exist, studies suggest that nucleoside analogues and phosphocitrate can attenuate calcification of human cartilage ex-vivo. Hindering research, is the lack of a well-defined description of CPPD. However, international working groups have convened to establish classification criteria and validated outcome domains for CPPD. This should help facilitate the setting up of large multicentre studies, with well-defined cohorts, which can evaluate suitable therapies, providing high levels of evidence to guide clinicians. Here, we summarise and discuss the currently available anti-inflammatory treatment options for CPPD and discuss potential future crystal-targeted approaches.

Laser treatment of synovial inflammatory process in experimentally induced microcrystalline arthritis in Wistar rats

The presence of intra-articular crystals is detected in different articular pathologies of acute or chronic nature. The aim of this work was to analyze the action of the indium gallium aluminum and phosphorus (InGaAlP) (λ = 670 nm) laser on the synovial membrane present in the knee joint in experimentally induced microcrystalline arthritis in male adult Wistar rats. The animals were divided into three experimental groups (n = 24): control (A), experimentally induced arthritis (B), experimentally induced arthritis+InGaAlP laser therapy (C). The laser treatment was made daily in the patellar region of the right knee after 48 h of the experimental induction. After 7, 14, and 21 days of therapy, the rats were euthanized and the right knees were removed and processed for histomorphometric, immunohistochemical, ultrastructural, and biochemical investigation of the synovium. The number of granulocytes on the 14th and 21st days was higher in B and lower in C and, lastly, in A. The number of fibroblasts on the 14th and 21st days was similar between A and C and below B. The number of blood vessels on the 21st day was higher in B than in the other groups. The positive number of cells for the TUNEL test was higher on the 14th and 21st days in B compared to the others. The percentage of tissue area occupied by birefringent collagen fibers was higher in B on the 21st day than in the others. The ultrastructure of cells showed fibroblast-like morphology in all groups and periods evaluated. The quantification of glycosaminoglycans did not present significant differences between the groups in all the experimental periods. The amount of hydroxyproline was higher in B compared to the other groups on the 14th and 21st days. The content of non-collagen proteins was higher in B on the 21st day in relation to the other groups. Quantification of TNF-α on the 21st day was higher in A and B than in C. For TGF-β on the 21st day, groups B and C presented similar and higher values than A. For MMP-13, groups A and B presented data similar to and above C. In relation to ADAMT-S4, on the 21st day, groups B and C presented data similar to and lower than A. InGaAlP-670 nm therapy reduced the inflammatory process and tissue injuries of the synovial membrane in comparison to the untreated group, indicating its potential utilization in clinical studies aiming in the recovery of acute arthritis in patients.

Management of calcium pyrophosphate crystal deposition disease: A systematic review

OBJECTIVE

Calcium pyrophosphate crystal deposition disease (CPPD) is a common cause of acute and chronic arthritis, especially in the elderly population. There is a paucity of data regarding the management of CPPD disease, which is currently based on expert opinion and evidence derived from the treatment of gout. We conducted a systematic literature review in order to identify the available treatment options for CPPD, and describe their efficacy and safety.

MATERIAL AND METHODS

Online databases were searched from inception to May of 2020 using the search terms: (CPPD [Title/Abstract] OR CPDD [Title/Abstract] OR calcium pyrophosphate [Title/Abstract] OR chondrocalcinosis [Title/Abstract]) AND (treatment [Title/Abstract] OR management [Title/Abstract] OR therapy [Title/Abstract]). Articles evaluating the use of specific treatment agents for CPPD were eligible for inclusion. Case reports were excluded.

RESULTS

A total of 22 eligible studies and 403 unique patients were selected. We identified only 3 randomized, double-blind, controlled trials (RCTs) evaluating the use of methotrexate, hydroxychloroquine, and magnesium carbonate in CPPD, and these therapeutic options, with the exception of methotrexate, have shown efficacy and reduction of pain intensity. Further, 10 case series and 9 cohort studies were included. Intramuscular and intra-articular glucocorticoids, ACTH, as well as the biologic agents anakinra and tocilizumab appear to be efficacious in CPPD. Intra-articular injections of glycosaminoglycan polysulphate, hyaluronic acid and yttrium, as well as synovial membrane destruction by laser irradiation were associated with symptomatic improvement. Due to significant study heterogenicity, direct comparison between studies was not possible.

CONCLUSION

There are a limited number of studies evaluating the treatment of CPPD. High quality evidence is rather limited, while commonly administered agents such as NSAIDs, colchicine and corticosteroids have not been evaluated by RCTs. The need for high quality evidence supporting specific treatment modalities is urgent for this common yet neglected form of arthritis.

Outcome domains reported in calcium pyrophosphate deposition studies: A scoping review by the OMERACT CPPD working group

INTRODUCTION

Although calcium pyrophosphate deposition (CPPD) is common, there are no validated outcome domains and/or measurements for CPPD studies. The aim of this work was to identify domains that have been reported in prior clinical studies in CPPD, to inform the development of a core set of domains for CPPD studies.

METHODS

We performed a scoping literature review for clinical studies in CPPD, searching in Medline (via PubMed), EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) databases; published from January 1, 1946 to January 7, 2020. All reported outcomes and study design data were extracted and mapped to the core areas and domains as defined by the OMERACT Filter 2.1.The protocol was registered on PROSPERO (CRD: 42019137075; 09-07-2019).

FINDINGS

There were 112 papers identified, comprising of 109 observational studies and three randomized controlled trials. Most studies reported clinical presentations of OA with CPPD or acute CPP crystal arthritis. Outcomes that mapped to 22 domains were identified; the most frequently reported measures mapped to the following domains/sub-domains: imaging (joint damage on imaging tests - 59 studies; joint calcification on imaging tests - 28 studies), joint pain (26 studies), response to treatment (23 studies), side effects of treatment (15 studies), inflammation in the joint fluid or blood (ESR or C-reactive protein - 12 studies; synovial fluid markers - 4 studies; other blood markers - 2 studies), overall function (14 studies), joint swelling (12 studies) and range of joint movement (10 studies). Very few studies mapped to domains related to life impact, societal/resource use or longevity.

CONCLUSION

There is substantial variability in outcomes reported in CPPD studies. Outcomes that map to imaging manifestations, joint pain and response to treatment domains are most often reported.

Effects of low-level laser therapy on the organization of articular cartilage in an experimental microcrystalline arthritis model

The aim of this study was to evaluate the effects of low-level laser therapy using the gallium arsenide laser (λ = 830 nm) on the articular cartilage (AC) organization from knee joint in an experimental model of microcrystalline arthritis in adult male Wistar rats. Seventy-two animals were divided into three groups: A (control), B (induced arthritis), and C (induced arthritis + laser therapy). The arthritis was induced in the right knee using 2 mg of Na₄P₂O₇ in 0.5 mL of saline solution. The treatments were daily applied in the patellar region of the right knee after 48 h of induction. On the 7th, 14th, and 21st days of treatment, the animals were euthanized and their right knees were removed and processed for structural and biochemical analysis of the AC. The chondrocytes positively labeled for the TUNEL reaction were lower in C than in B on the 14th and 21st days. The content of glycosaminoglycans and hydroxyproline in A and C was higher than B on the 21st day. The amount of tibial TNF-α in B and C was lower than in A. The amount of tibial BMP-7 in B and C was higher than in A. The femoral MMP-13 was lower in B and C than for A. The tibial TGF-β for C was higher than the others. The femoral ADAMT-S4 content of A and C presented similar and inferior data to B on the 21st day. The AsGa-830 nm therapy preserved the content of glycosaminoglycans, reduced the cellular changes and the inflammatory process compared to the untreated group.

Photobiomodulation Inhibits Long-term Structural and Functional Lesions of Diabetic Retinopathy

Previous studies demonstrated that brief (3 to 4 min) daily application of light at 670 nm to diabetic rodents inhibited molecular and pathophysiologic processes implicated in the pathogenesis of diabetic retinopathy (DR) and reversed diabetic macular edema in small numbers of patients studied. Whether or not this therapy would inhibit the neural and vascular lesions that characterize the early stages of the retinopathy was unknown. We administered photobiomodulation (PBM) therapy daily for 8 months to streptozotocin-diabetic mice and assessed effects of PBM on visual function, retinal capillary permeability, and capillary degeneration using published methods. Vitamin D receptor and Cyp24a1 transcripts were quantified by quantitative real-time PCR, and the abundance of c-Kit⁺ stem cells in blood and retina were assessed. Long-term daily administration of PBM significantly inhibited the diabetes-induced leakage and degeneration of retinal capillaries and also significantly inhibited the diabetes-induced reduction in visual function. PBM also inhibited diabetes-induced reductions in retinal Cyp24a1 mRNA levels and numbers of circulating stem cells (CD45^-/c-Kit⁺), but these effects may not account for the beneficial effects of PBM on the retinopathy. PBM significantly inhibits the functional and histopathologic features of early DR, and these effects likely are mediated via multiple mechanisms.

A Meta-analysis of Clinical Effects of Low-level Laser Therapy on Temporomandibular Joint Pain

[Purpose] Temporomandibular joint (TMJ) pain is a symptom of TMJ disease. Low-level laser therapy (LLLT) is often used in the clinical treatment of TMJ pain. The aim of this study was to review the effective parameters of LLLT for TMJ pain. [Methods] This study was a systematic review in which electronic databases were searched for the period of January 2005 to January 2010. We selected reports of randomized controlled trials and calculated the effect size (ES) of the pain relief to evaluate the effect of LLLT. [Results] Seven reports are found to meet the inclusion criteria and discussed. Based on the calculation results, the pooled ES was -0.6, indicating a moderate effect of pain relief. In addition, the dosages and treatments with wavelengths of 780 and 830 nm can cause moderate and large pain relief effects. [Conclusion] Use of LLLT on the masticatory muscle or joint capsule for TMJ pain had a moderate analgesic effect. The optimal parameters for LLLT to treat TMJ pain have not been confirmed. However, our results can be a vital clinical reference for clinical physicians in treatment of patients with TMJ pain.

Low-level laser therapy prevents degenerative morphological changes in an experimental model of anterior cruciate ligament transection in rats

The aim of this study was to analyze the effects of low-level laser therapy (LLLT) on the prevention of cartilage damage after the anterior cruciate ligament transection (ACLT) in knees of rats. Thirty male rats (Wistar) were distributed into three groups (n = 10 each): injured control group (CG); injured laser-treated group at 10 J/cm(2) (L10), and injured laser-treated group at 50 J/cm(2) (L50). Laser treatment started immediately after the surgery and it was performed for 15 sessions. An 808 nm laser, at 10 and 50 J/cm(2), was used. To evaluate the effects of LLLT, the qualitative and semi-quantitative histological, morphometric, and immunohistochemistry analysis were performed. Initial 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.

Effect of IR laser on myoblasts: a proteomic study

Laser therapy is used in physical medicine and rehabilitation to accelerate muscle recovery and in sports medicine to prevent damages produced by metabolic disturbances and inflammatory reactions after heavy exercise. The aim of this research was to get insight into possible benefits deriving from the application of an advanced IR laser system to counteract deficits of muscle energy metabolism and stimulate the recovery of hypotrophic tissue. We studied the effect of IR laser treatment on proliferation, differentiation, cytoskeleton organization and global protein expression in C2C12 myoblasts. We found that laser treatment induced a decrease in the cell proliferation rate without affecting cell viability, while leading to cytoskeletal rearrangement and expression of the early differentiation marker MyoD. The differential proteome analysis revealed the up-regulation and/or modulation of many proteins known to be involved in cell cycle regulation, cytoskeleton organization and differentiation.

Effects of low-level laser therapy on cartilage repair in an experimental model of osteoarthritis

Objective:

The aim of this study was to evaluate the effects of low level laser therapy (LLLT) on the degenerative process in the articular cartilage after an anterior cruciate ligament transection (ACLT) model in rats.

Methods:

Eighty male rats (Wistar) were divided into four groups: 1.) intact control group (CG), 2.) injured control group (ICG), 3.) injured laser-treated group at 10 J/cm

Results:

Initial signs of tissue degradation could be observed 5 weeks post-ACLT, evidenced by the decrease of proteoglycan concentration and increase in cartilage thickness of the ICG. After 8 weeks post-surgery, analysis showed a progression of the degenerative processes in the ICG revealed by the increased cellularity and higher TNF-α, IL1-β and MMP-13 immunoexpression. LLLT was able to modulate some of the aspects relating to the degradative process, such as biomodulation of the number of chondrocyte proliferation, prevention of proteoglycan loss, and decrease of MMP-13 immunoexpression.

Conclusion:

This study showed that the 685-nm laser irradiation, especially at 10 J/cm

Low level laser therapy on experimental myopathy

PURPOSE

The aim of the present work was to study the effect of Helium-Neon (HeNe) and Gallium Arsenide (GaAs) laser upon nitric oxide (NO) plasma levels, an inflammatory biomarker associated with oxidative stress, in rats with experimental myopathy. These were evaluated through histological assessment.

MATERIALS AND METHODS

The groups studied were: (A) control (intact rats that received LLLT sham exposures), (B) rats with myopathy and sacrificed at 24 h later, (C) rats with myopathy and sacrificed 8 days later, (D) rats with myopathy and treated with HeNe laser, (E) rats with myopathy and treated with GaAs laser, (F) intact rats treated with HeNe laser and (G) intact rats treated with GaAs laser. Myopathy was induced by injecting 50μl of 1% carrageenan λ (type IV) in the left gastrocnemius muscle. Low Level Laser Therapy (LLLT) was applied with 9.5 J.cm(-2) daily for 10 consecutive days with each laser. The determination of the NO was made by spectrophotometry. The muscles were stained with Hematoxylin-Eosin and examined by optic microscopy. Quantitative variables were statistically analyzed by the Fisher test, and categorical by applying Pearson's Chi Squared test at p <0.05 for all cases.

RESULTS

In groups B and C, NO was significantly increased compared to groups A, D, E, F and G (p<0.05). In group C, the percentage of area with inflammatory infiltration was significantly increased compared to the other groups (p<0.001).

CONCLUSIONS

LLLT decreased plasma levels of NO in rats with experimental myopathies and significant muscle recovery.

Avaliação funcional da nocicepção do joelho de ratos tratada com laser de baixa potência e natação

O objetivo deste estudo foi avaliar e comparar os efeitos do laser de baixa potência e da natação forçada em modelo de nocicepção articular, de ratos Wistar, avaliando a dor de forma funcional, pelo tempo de elevação da pata (TEP) durante marcha em cilindro metálico. Foram utilizados 32 ratos Wistar, divididos em quatro grupos: GC - animais submetidos à indução de nocicepção no joelho direito e não tratados; GL - nocicepção e tratados com laser de baixa potência 670nm, 8J/cm²; GN - nocicepção e natação por 10 minutos em água a 30-32ºC; GNL - nocicepção e tratados com natação e laser. Para realizar a nocicepção foi injetado, no espaço tibiofemoral medial direito, 50µL de formalina 5%. A avaliação funcional da dor foi realizada com o teste de incapacidade funcional, que avalia o tempo de pata no ar (TEP) da marcha durante um minuto sobre um cilindro metálico, as avaliações ocorreram antes da indução da nocicepção (AV1), após 15 (AV2) e 30 minutos (AV3) da mesma, sendo que após a AV2, ocorreram os protocolos de tratamento. Os resultados mostraram que o grupo laser foi o único a apresentar restauração dos valores na AV3, comparando com AV1. GN foi o único a não apresentar redução ao comparar AV3 com AV2. Conclui-se que, pela avaliação funcional, o laser de baixa potência apresentou efeitos analgésicos, enquanto a natação produziu aumento do quadro de dor, o qual foi parcialmente revertido com o uso do laser associado

Evaluation of inflammatory biomarkers associated with oxidative stress and histological assessment of low-level laser therapy in experimental myopathy

The objective of the present work was to study the effect of helium-neon (He-Ne) and gallium-arsenide (Ga-As) laser upon inflammatory biomarkers associated with oxidative stress: fibrinogen, nitric oxide (NO), L-citrulline, and superoxide dismutase (SOD). These were evaluated through histological assessment, in rats with experimental myopathy.

MATERIALS AND METHODS

The groups studied were: (A) control, (B) injured, (C) injured and treated with He-Ne laser, (D) injured and treated with Ga-As laser, (E) irradiated with He-Ne; and (F) irradiated with Ga-As laser. Myopathy was induced by injecting 0.05 mg/rat/day of adrenaline in the left posterior limb muscle at the same point on 5 consecutive days, in groups B, C, and D. Low-level laser therapy (LLLT) was applied with 9.5 J/cm(2) daily for 7 consecutive days with each laser. The determination of the biomarkers was made by spectrophotometry. The muscles (5/8, single blinded) were stained with Gomori Trichrome and examined by optic microscopy. The quantitative variables were statistically analyzed by the Fisher's test and categorical data by the Axionvision 4.8 program. Pearson's chi-squared test was applied, setting significant difference at P < 0.05 for all cases.

RESULTS

In group B, the biomarkers were significantly increased compared to the other groups (P < 0.001), except for NO which in group B decreased significantly (P < 0.001). In group B, there was a higher inflammatory infiltration level (80.67%) in relation to destroyed fibers.

CONCLUSIONS

LLLT 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.

Inflammatory and oxidative stress markers in experimental crystalopathy: their modification by photostimulation

Crystalopathies are inflammatory pathologies caused by cellular reactions to the deposition of crystals in the joints. The anti-inflammatory effect of the helium-neon (He-Ne) laser and that of the nonsteroidal anti-inflammatory drugs (NSAIDs) diclofenac, meloxicam, celecoxib, and rofecoxib was studied in acute and chronic arthritis produced by hydroxyapatite and calcium pyrophosphate in rats. The presence of the markers fibrinogen, L-citrulline, nitric oxide, and nitrotyrosine was determined. Crystals were injected into the posterior limb joints of the rats. A dose of 8 J/cm(2) of energy from an He-Ne laser was applied for 3 d in some groups and for 5 d in other groups. The levels of some of the biomarkers were determined by spectrophotometry, and that of nitrotyrosine was determined by ELISA. For statistical analysis, Fisher's exact test was used, and p +/- 0.05 was considered significant. In arthritic rats, the fibrinogen, L-citrulline, nitric oxide, and nitrotyrosine levels increased in comparison to controls and to the laser-treated arthritic groups (p +/- 0.001), (p +/- 0.001), (p +/- 0.02), and (p +/- 0.01), respectively. When comparing fibrinogen from arthritic rats with disease induced by hydroxyapatite with undiseased and arthritic rats treated with NSAIDs, the He-Ne laser decreased levels to values similar to those seen in controls (p +/- 0.01). Inflammatory and oxidative stress markers in experimental crystalopathy are positively modified by photobiostimulation.

Helium-neon laser reduces the inflammatory process of arthritis

OBJECTIVE

A histological study of the anti-inflammatory effect of helium-neon laser in models of arthropathies induced by hydroxyapatite and calcium pyrophosphate in rats.

BACKGROUND

Crystal deposition diseases are inflammatory pathologies induced by cellular reaction to the deposit of crystals in the joints.

METHODS

Fifty-six Suquia strain rats were distributed in seven groups. Two mg of each crystal diluted in 0.05 ml physiologic solution were injected six times in each back limb joint, during two weeks on alternate days. Eight J/cm(2) were applied daily to the crystal-injected joints on five consecutive days. The joints were cut and put in 10% formaldehyde, stained with hematoxylin-eosin and observed by light microscopy. The percentage of area with inflammatory infiltrates was determined in five optical microscopy photographs (100X) for each group and analyzed using the Axionvision 4.6 program. A Pearson's Chi Squared test was applied, with significance level set at p < 0.05.

RESULTS

Both crystals produced an inflammatory process in the osteoarticular structures, consisting of predominantly mononuclear infiltration, fibrosis, and granulomas of foreign body-type giant cells containing phagocytosed remains of crystals. In the arthritic joints treated with laser, a marked decrease (p < 0.0001) was found in the percentage of area with inflammatory infiltrates, although the granulomas remained in a less ostensible form, with adipose tissue cells, fibrosis bands with light residual inflammation, and an absence of or very few crystals. Laser alone or physiologic solution injection did not produce histological changes.

CONCLUSIONS

Helium-neon laser reduced the intensity of the inflammatory process in the arthritis model induced by hydroxyapatite and calcium pyrophosphate crystals.

Low-level laser irradiation inhibits abdominal aortic aneurysm progression in apolipoprotein E-deficient mice

AIMS

Increased early detection of abdominal aortic aneurysm (AAA) and the severe complications of its current treatment have emphasized the need for alternative therapeutic strategies that target pathogenetic mechanisms of progression and rupture. Recent in vitro studies from our laboratory have shown that low-level laser irradiation (LLLI) (780 nm) modifies cellular processes fundamental to aneurysm progression. The present study was designed to determine whether LLLI retards the progression of suprarenal AAA in vivo.

METHODS AND RESULTS

High-frequency ultrasonography (0.01 mm resolution) was used to quantify the effect of LLLI on aneurysmatic aortic dilatation from baseline to 4 weeks after subcutaneous infusion of angiotensin II by osmotic minipumps in the apolipoprotein E-deficient mouse. At 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 Fisher's 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.

CONCLUSION

These in vivo studies, together with previous in vitro studies from this laboratory, appear to provide strong evidence in support of a role for LLLI in the attenuation of aneurysm progression. Further studies in large animals would appear to be the next step towards testing the applicability of this technology to the human interventional setting.

Low-level laser therapy for zymosan-induced arthritis in rats: Importance of illumination time

BACKGROUND

It has been proposed for many years that low-level laser (or light) therapy (LLLT) can ameliorate the pain, swelling, and inflammation associated with various forms of arthritis. Light is thought to be absorbed by mitochondrial chromophores leading to an increase in adenosine triphosphate (ATP), reactive oxygen species and/or cyclic AMP production and consequent gene transcription via activation of transcription factors. However, despite many reports about the positive effects of LLLT in arthritis and in medicine in general, its use remains controversial. For all indications (including arthritis) the optimum optical parameters have been difficult to establish and so far are unknown.

METHODS

We tested LLLT on rats that had zymosan injected into their knee joints to induce inflammatory arthritis. We compared illumination regimens consisting of a high and low fluence (3 and 30 J/cm(2)), delivered at high and low irradiance (5 and 50 mW/cm(2)) using 810-nm laser light daily for 5 days, with the positive control of conventional corticosteroid (dexamethasone) therapy.

RESULTS

Illumination with 810-nm laser was highly effective (almost as good as dexamethasone) at reducing swelling and a longer illumination time (10 or 100 minutes compared to 1 minute) was more important in determining effectiveness than either the total fluence delivered or the irradiance. LLLT induced reduction of joint swelling correlated with reduction in the inflammatory marker serum prostaglandin E2 (PGE2).

CONCLUSION

LLLT with 810-nm laser is highly effective in treating inflammatory arthritis in this model. Longer illumination times were more effective than short times regardless of total fluence or irradiance. These data will be of value in designing clinical trials of LLLT for various arthritides.