Efeito antinociceptivo e anti-inflamatório da quercetina na artrite reumatoide induzida por mBSA na ATM de ratos

Abstract

Rheumatoid arthritis (RA) is a polyarticular, chronic, autoimmune and systemic synovitis, in which the temporomandibular joint (TMJ) is commonly involved. Quercetin (QT) has been used as an alternative or adjunctive treatment in chronic inflammatory diseases. The objective of this work was to evaluate the antinociceptive and anti-inflammatory effect of QT on RA induced by methylated bovine serum albumin (mBSA) in the ATM of rats. Thirty male Wistar rats (7-8 weeks old) were used and randomly divided into the control, AR, QT, MX and QT + MX groups. Initially, the animals were sensitized with subcutaneous injections on the back with an emulsion containing mBSA and Freund's complete/incomplete adjuvant. For the induction of RA, three intra-articular challenges at the ATM were performed with a solution containing mBSA (1 injection / week). Treatment with QT (25 mg/kg; orally) and/or MX (0.75 mg; orally) occurred daily from the 24th hour after the first TMJ intra-articular challenge. Mechanical TMJ hyperalgesia, total leukocyte count in synovial fluid and blood, histopathology of TMJ, immunoexpression of TNF-α and IL-10 in the synovial membrane and parameters of renal and liver toxicity were evaluated. There was a significant reduction in the nociceptive threshold after RA induction in the TMJ. The AR group had an intense inflammatory infiltrate in the synovial membrane and joint damage. Treatment with QT and/or MX significantly increased the nociceptive threshold of arthritic animals and reduced inflammatory parameters in the TMJ. However, a better response was observed in the administration of both drugs. RA was associated with intense immunoexpression of TNF-α in the synovial membrane, while QT and/or MX inhibited it. Untreated arthritic animals showed an increase in IL-10. Isolated QT did not interfere with the immunoexpression of this anti-inflammatory cytokine and the use of MX suppressed it. The AR group showed a total increase in leukocytes in synovial fluid and blood. The treated groups showed a reduction in this cell migration. Renal changes were not observed. However, significant liver changes were associated with the AR and MX groups and QT administration reduced them. Thus, we conclude that QT has antinociceptive and anti-inflammatory effects in this experimental model, and may be an adjunct drug to MX in the treatment of RA.