Effects of taurochenodeoxycholic acid on adjuvant arthritis in rats

Taurochenodeoxycholic acid (TCDCA) is one of the main bioactive substances of animals' bile acid. In this study, we aimed to investigate the anti-arthritic effects and potential mechanism of TCDCA on adjuvant arthritis (AA) in rats. Freund's complete adjuvant (FCA) was used to induce AA in rats. Paw swelling, index of thymus and spleen and body weight growth rate were measured, and polyarthritis index and radiologic changes were observed. The production of TNF-α, IL-1β, IL-6 and IL-10 was detected by ELISA in serum and synoviocytes. mRNA expression of TNF-α, IL-1β, IL-6 and IL-10 was determined by real-time RT-PCR in synovium tissue and synoviocytes. In both prophylactic and therapeutic treatment, TCDCA significantly suppressed paw swelling and polyarthritis index, increased the loss body weight and index of thymus and spleen, and amended radiologic changes in AA rats. The overproduction and mRNA expression of TNF-α, IL-1β and IL-6 were remarkably suppressed in serum and synovium tissue of all TCDCA-treated rats, however, IL-10 was markedly increased in prophylactic treatment. In a definite concentration ranging from 300 μg/mL to 500 μg/mL, TCDCA showed marked inhibition in the overproduction and mRNA expression of TNF-α, IL-1β and IL-6 in synoviocytes in a concentration-dependent manner, but opposite action on IL-10. In conclusion, treatment with TCDCA confers a good anti-adjuvant arthritis activity in rats, which its reparative effects could be mediated via reduction of the protein and mRNA expression of TNF-α, IL-1β and IL-6, and augment of IL-10 in rats.