A total of 50 SD rats were randomly divided into control group （given normal saline）， model group （given normal saline）， low， medium， and high doses of TSC groups （given 50， 100， and 200 mg·kg^－1 TSC）， and there were 10 rats in each group. In addition to control group， the RA rat models were established in the other groups. The swelling degrees of ankle joint of the rats in various groups were measured and the arthritis indexes were calculated after 6 weeks of administration. Flow cytometry was used to detect the percentages of CD4⁺ T lymphocytes and CD8⁺ T lymphocytes in peripheral blood of the rats in various groups；ELISA method was used to detect the levels of serum tumor necrosis factor-α（TNF-α），interleukin-1β（IL-1β）， and interleukin-6（IL-6） of the rats in various groups； the spleen weights of the rats in various groups were measured and the spleen index was calculated.

Compared with control group， the arthritis index of the rats in model group was significantly increased （P<0.05）， the percentage of CD4⁺ T lymphocytes and the ratio of CD4⁺/CD8⁺ T lymphocytes were significantly increased （P<0.05）， the percentage of CD8⁺ T lymphocytes was significantly decreased （P<0.05）， and the levels of serum TNF-α，IL-1β，and IL-6 and the spleen index were significantly increased （P<0.05）. Compared with model group， the arthritis indexes of the rats in low， medium and high doses of TSC groups were significantly decreased （P<0.05）， the percentages of CD4⁺ T lymphocytes and the ratioes of CD4⁺/CD8⁺ T lymphocytes were significantly decreased （P<0.05）， the percentages of CD8⁺ T lymphocytes was significantly increased （P<0.05）， and the levels of serum TNF-α， IL-1β，and IL-6 and the spleen indexes were significantly decreased （P<0.05）. Compared with low dose of TSC group， the arthritis indexes of the rats in medium and high doses of TSC groups were significantly decreased （P<0.05）， the percentages of CD4⁺ T lymphocyte and the ratios of CD4⁺/CD8⁺ T lymphocytes were significantly decreased （P<0.05）， the percentages of CD8⁺ T lymphocytes were significantly increased （P<0.05）， and the levels of serum TNF-α， IL-1β and IL-6 and the spleen indexes were significantly decreased （P<0.05）. Compared with medium dose of TSC group， the arthritis index of the rats in high dose of TSC group were significantly decreased （P<0.05）， the percentage of CD4⁺ T lymphocytes and the ratio of CD4⁺/CD8⁺ T lymphocytes were significantly decreased （P<0.05）， the percentage of CD8⁺ T lymphocytes was significantly increased （P<0.05）， and the levels of serum TNF-α， IL-1β ，and IL-6 and the spleen index were significantly decreased （P<0.05）.

TSC can inhibit RA by regulating the percentages of CD4⁺ and CD8⁺ T lymphocytes and inhibiting the secretion of inflammatory cytokines in a dose-dependent manner.