Effects of Tongbi Mixture 2 on expressions of CD28 and CD152 and content of tumor necrosis factor-alpha in peripheral blood in rats with collagen-induced arthritis

OBJECTIVE: To study the effects of Tongbi Mixture 2, a compound traditional Chinese herbal medicine for treating rheumatoid arthritis (RA), on immunoregulation of T lymphocytes in rats with collagen-induced arthritis (CIA). METHODS: Forty Wistar rats were randomly divided into normal control group, untreated group, Tongbi Mixture 2-treated group, methotrexate (MTX)-treated group and Tripterygium wilfordii polyglycoside (TWP)-treated group. Except for the rats of the normal control group (injection with normal saline), rats of the other four groups were subcutaneouly multipoint-injected with collagen protein II to induce CIA. The rats were treated with normal saline, Tongbi Mixture 2, MTX tablets and TWP tablets respectively for 36 days. The expressions of CD28 and CD152 were detected by flow cytometry, while the content of tumor necrosis factor-alpha (TNF-alpha) was analyzed by enzyme-linked immunosorbent assay. RESULTS: The expression of CD28 among the three drug treated groups had no statistical difference (P>0.05), while significantly higher than that of the normal control group (P<0.01) and lower than that of the untreated group (P<0.01). The expression of CD152 in the Tongbi Mixture 2 treated-group was lower than those of the MTX- and TWP-treated groups (P<0.05, P<0.01), but had no statistical difference as compared with the normal control group (P>0.05). There were no statistical differences in content of TNF-alpha between the drug treated groups and the normal control group (P>0.05), but the content of TNF-alpha of the drug treated groups was lower than that of the untreated group (P<0.05 or P<0.01). CONCLUSION: Tongbi Mixture 2 can inhibit T lymphocytes through down-regulating the expressions of CD28 and CD152 and the content of TNF-alpha, which may be the major mechanisms in treating RA.