Abstract: Objective To evaluate therapeutic effects of simvastatin on rat with collagen induced arthritis(CIA) and to supply theoretical basis for exploring new treatments of rheumatoid arthritis. Method Arthritis was induced by injecting bovine Ⅱ collagen into Wistar rat.The rat were randomly divided into three groups: normal control,CIA control,simvastatin groups.Every seven days after first injection record once arthritis index(AI) and the volumes of hind paw; Measure the changes in serum cytokine levels including TNF-α，IL-6 by ELISA and detect the expression of caspase-3 in ankle synovial tissue by immunohistochemical and use HE staining analyse ankle pathological on fortieth day. Results The serum levels of TNF-α,IL-6 and AI and the volumes of hind paw in simvastatin group were decreased on fortieth day.The expression of caspase-3 in simvastatin group was high and synovial hyperplasia was light than that of the CIA control group. Conclusion: simvastatin can decrease serum levels of TNF-α,IL-6 in CIA rat.Also can inhibite synovial hyperplasia and increse the expression of caspase-3 in ankle of the CIA rat.

Key words: simvastatin, arthritis, anti-inflammatory, TNF-α, IL-6, caspase-3