Morphometric aspects of the articular cartilage of rats treated with low-level laser therapy and exercise in a rheumatoid arthritis model

INTRODUCTION: Rheumatoid arthritis (RA) is classified as an autoimmune, chronic disease affecting diarthrodial joints and periarticular structures. OBJECTIVE: To evaluate whether low-intensity laser treatment (LLLT) and/or exercise reduce the deleterious effects of tissue in a rheumatoid arthritis model. METHODS: 128 rats were divided into two inflammatory periods: acute (7 days) and chronic (28 days) and subdivided into control, injury and treatment. The protocol with Freund's Complete Adjuvant was used in two inoculations, one intradermal and one intraarticular in the tibiofemoral joint, the control animals received saline solution. For treatment, LLLT 660 nm, 5 J/cm² was used in the sensitized joint and climbing exercise in stairways with an overload of 100 grams. After the experimental period, the animals were euthanized and the joints were prepared for morphometric analysis of the total thickness, superficial, deep, and cellular density of the articular cartilage. Generalized Linear Models with Sidak post-test were chosen. RESULTS: The control group was found to be different from the lesion group with greater joint cartilage thickness, andthe animals treated with exercise alone increased the joint cartilage compared to thecontrol group. CONCLUSION: The animals treated with laser association and exercise showed improvement in the morphometric aspects of the articular cartilage.

Exercício resistido promove reparo no musculoesquelético em modelo experimental de artrite reumatoide / Resisted exercise promotes repair in musculoskeletal structure in experimental model of rheumatoid arthritis

Distúrbios decorrentes da artrite reumatoide (AR) resultam em incapacitação funcional, com reflexos econômicos e sociais aos sistemas de saúde. Uma alternativa terapêutica que tem sido proposta é a atividade física na modalidade resistida. O presente estudo analisou os efeitos do exercício resistido de subida em escada (ERSE) na histomorfologia do músculo extensor longo dos dedos (EDL) de ratos Wistar, em modelo experimental de AR. Ratos machos (n=20) foram distribuídos aleatoriamente em quatro grupos. A lesão da AR foi induzida por administração intra-articular de Adjuvante Completo de Freund (CFA). Os resultados revelaram que a AR alterou a histomorfometria das fibras do EDL e que o ERSE promoveu reparo muscular, sugerindo sua eficiência na restauração da funcionalidade muscular. Ainda, o ERSE pode ser uma opção de tratamento voltado à melhoria na qualidade de vida dos portadores de AR.

Disorders from rheumatoid arthritis (RA) result in functional disability, with economic and social impacts on health systems. A therapeutic alternative that has been proposed is physical activity in the resisted modality. Current study analyzed the effects of resistance exercise on stairs (ERSE) on the histomorphology of the extensor digitorum longus muscle (EDL) of Wistar rats in an experimental model of RA. Male rats (n=20) were randomly assigned to four groups. RA injury was induced by intra-articular administration of Freund's Complete Adjuvant (CFA). Results revealed that RA altered the histomorphometry of EDL fibers and that ERSE promoted muscle repair, suggesting its efficiency in restoring muscle functionality. Furthermore, ERSE may be a treatment option to improve the life quality of people with RA.

Low-level laser therapy in periarticular morphological aspects of the knee of Wistar rats in rheumatoid arthritis model / Laser de baixa intensidade nos aspectos morfológicos periarticulares do joelho de ratos Wistar em modelo de artrite reumatoide

ABSTRACT BACKGROUND AND OBJECTIVES: The deleterious effects of rheumatoid arthritis on periarticular tissues have not yet been fully elucidated. Therefore, the search for treatments that can modulate the inflammatory profile and tissue remodeling is pertinent. The present study evaluated the effects of low-level laser therapy (LLLT) on the morphology of periarticular tissues and synovial membrane of rats in a rheumatoid arthritis model. METHODS: Sixty-four male rats were divided into acute (7 days) and chronic (28 days) inflammatory periods, with four groups (n=8) each, being: CG (control group), LG (lesion group), CLaG (laser control group) and LLaG (laser lesion group). The animals of the lesion groups received two inoculations of Freund's Complete Adjuvant at a concentration of 50µL, the first at the base of the tail, and the second at the right knee. The animals in the control groups were injected with isotonic sodium chloride solution. The ClaG and LLaG were treated with 660nm LBI, 5J/cm2 in the right knee. After the experimental period, the animals were euthanized, and the knees were processed for light microscopy. RESULTS: The CG and CLaG morphological analysis had normal aspects. The LG showed synovitis, femur, and tibia with changes in the periosteum, with inflammatory cells and bone modifications. In the LLaG, the synovial membrane showed signs of improvement. Bone tissue in the chronic period showed morphological aspects, denoting tissue remodeling. CONCLUSION: The experimental model was efficient in simulating inflammatory tissue events, and the low-level laser therapy showed beneficial effects on the morphology of the periarticular tissues.

RESUMO JUSTIFICATIVA E OBJETIVOS: Os efeitos deletérios da artrite reumatoide nos tecidos periarticulares ainda não estão totalmente elucidados, sendo pertinente a busca por tratamentos que possam modular o perfil inflamatório e a remodelação tecidual. O presente estudo avaliou os efeitos do laser de baixa intensidade (LBI) na morfologia dos tecidos periarticulares e membrana sinovial de ratos submetidos à um modelo de artrite reumatoide. MÉTODOS: Para tanto, 64 ratos machos foram divididos em períodos inflamatórios agudo (7 dias) e crônico (28 dias), com 4 grupos (n=8) cada, sendo: GC (grupo controle), GL (grupo lesão), GCLa (grupo controle laser) e GLLa (grupo lesão laser). Os animais dos grupos lesão foram submetidos a duas inoculações de Adjuvante Completo de Freund na concentração de 50µL, sendo a primeira na base da cauda e a segunda no joelho direito. Os animais do grupo controle foram submetidos a injeções com solução isotônica de cloreto de sódio. Os grupos GCla e GLLa foram tratados com LBI 660nm, pontual no joelho direito, 5J/ cm2. Após o período experimental, os animais foram eutanasiados e os joelhos processados para análises em microscopia de luz. RESULTADOS: Na análise morfológica, GC e GCLa apresentaram aspectos normais. O GL apresentou sinovite, fêmur e tíbia com alterações no periósteo, com células inflamatórias e modificações ósseas. A membrana sinovial mostrou sinais de melhora no GLLa. No período crônico, o tecido ósseo apresentou aspectos morfológicos, denotando remodelação tecidual. CONCLUSÃO: O modelo experimental foi eficiente em simular os eventos inflamatórios teciduais, e o laser de baixa intensidade apresentou efeitos benéficos sobre a morfologia dos tecidos periarticulares.