Efeitos do exercício resistido no perfil inflamatório e na articulação tibiofemoral em um modelo de artrite reumatoide

Abstract

Rheumatoid Arthritis (RA) is a chronic, systemic, autoimmune inflammatory disease, which mainly compromises the synovial tissue in multiple joints, causing pain, functional limitation or total immobility. Therefore, it is pertinent to research for treatments that modulate the inflammatory process and maintain and/or improve the patient's functionality. The objective of this study was to evaluate the effects of resistance exercise on the inflammatory profile and morphology of the tibiofemoral joint and popliteal lymph node in Wistar rats with experimental RA. The sample consisted of 32 male rats, with an average age of 14 weeks, separated into four groups (n= 8 animals): Control Group (CG), Rheumatoid Arthritis Group (RAG), Exercise Group (EXG), and Exercise and Rheumatoid Arthritis (EXRAG). The animals submitted to experimental RA received two applications of Complete Freund's Adjuvant (CFA). All animals were evaluated at five moments for edema and joint disability, muscle strength and nociceptive threshold. After the induction of RA was confirmed, the EXRAG animals were treated with resistance exercise, climbing stairs, undergoing 3 series of 8 climbs, with a load of 25%, 35% and 50% of the animal's weight, with an interval of 2 minutes between each series. After the treatment period, the animals were euthanized, the synovial fluid, popliteal lymph node and right tibiofemoral joint were collected, and processed for histomorphological analysis. The data were analyzed using the generalized linear model test with LSD post-test, considering significance at p<0.05. The RAG and EXRAG showed an increase in the diameter of the tibiofemoral joint, indicating the formation of edema and the development of RA. However, EXRAG showed an improvement in edema, suggesting an anti-inflammatory effect of the treatment. The RAG and GEXAR also showed greater sensitivity and loss of strength, as well as decreased joint capacity in the evaluations. However, the EXRAG animals had a faster recovery of strength, and at the end of the experiment, all groups returned to their initial strength. In the morphometric data of the lymph node, there was a significant difference in the CG with a smaller total area when compared to the other groups. In the organ marrow cell count, EXRAG showed similarity to RAG and EXG, with a greater tendency of lymphocytes and plasma cells in the medullary cord, and macrophages and reticular cells in the medullary sinus, when compared to CG. In the morphometric data of the tibiofemoral joint, the EXG showed a smaller cartilage thickness, and the RAG showed a greater number of chondrocytes. In morphological analyses, the lymph nodes showed characteristic anatomical normality, but with a larger size in the RAG, EXG and EXRAG, in addition to medullary cords that were more cellularized than the breasts. In the tibiofemoral joints, the synovial membranes of the RAG and EXRAG showed classic characteristics of synovitis. In RAG, morphological changes were observed in the femur and tibia, while in EXRAG, with cartilage within normal standards, similar to CG, showing only invagination of the subchondral bone. In conclusion, RA caused changes in the tibiofemoral joints and popliteal lymph nodes, an increase in the number of defense cells due to the inflammatory process, in addition to functional changes. However, resistance exercise optimized the recovery process of the morphofunctional aspects of the tibiofemoral joint, modulating the immune response in the popliteal lymph nodes, and improving motor, nociceptive and joint functionality