Objective: To observe the effects of Zhiyuanfang inhibiting platelets amplified inflammation and proliferation of synovial cells in the rheumatoid arthritis (RA) rats. Method: Normal cultured RSC364 cells were divided into normal control group

RA model group

activated platelet intervention group and Zhiyuanfang group.The different concentrations of tumor necrosis factor-α(TNF-α) were used to induce RA rat cell models

stimulate platelets activating by bovine type II collagen

and interfere platelet intervention group with Zhiyuanfang containing serum. The expression of interleukin-6(IL-6)

interleukin-8(IL-8) and P-selecting were assayed respectively by enzyme-linked immunosorbnent assay (ELISA)

and the proliferation of RSC364 cells were determined by MTT colorimetric assay. Result: ①The expression of P-selecting was at peak when platelets were activated by bovine type II collagen for 5 h.②the expression of IL-6 and IL-8 on synovial cells in RA model group was increased

which was compared with the same concentration of normal group showed a significant difference(P<0.05);the rate of RSC364 cells proliferation was also higher than normal group(P<0.05)in a dose-dependent manner.③Compared with RA model group

the expression of IL-6 and IL-8 on synovial cells in platelets intervention group was significantly increased(P<0.05

P<0.01)

and the rate of synovial cells proliferation was also higher(P<0.05).④ Compared with platelets intervention group

the expression of IL-6 and IL-8 on synovial cells in Zhiyuanfang group was significantly reduced (P<0.05

P<0.01)

the proliferation rate of synovial cells was declined(P<0.05)

and the expression of P-selecting was also lower. Conclusion: Activated platelets amplify the inflammation and proliferation of synoviocytes;Zhiyuanfang effectively can relieve the amplification of platelets on the inflammation and proliferation in RA rats probably by the inhibition of P-selecting expression.