Abstract: Objective: To investigate the effects of etanercept on collagen induced arthritis rats.Methods: The rheumatoid arthritis model was established via subcutaneous injection of bovine type Ⅱ collagen, and the effects of etanercept was compared through three groups:①the normal control;②arthritis model treated with saline;③arthritis model treated with etanercept (0.5 mg/kg, intraperitoneal injection) with 10 rats in each group;group②and group③ were selected by arthritis index (≥ 2)and grouped randomly. The body weight and toe volume were measured at just before and during treatment weekly. Rats were sacrificed after 4 weeks of treatment, and the serum levels of tumor necrosis factor α(TNF-α), angiopoietin-1(Ang-1), IL-1β, IL-6 and IL-8 were tested by ELISA. Nuclear factor-kappa B(NF-κB) levels and subcellular locations in toe muscles were test by Western blot.Results: Etanercept significantly relieved inflammation of rheumatoid arthritis, lowered the TNF-α and relative inflammatory factors levels compared with saline treatment (P<0.05). The results of Western blot showed that etanercept significantly suppressed the nuclear location of NF-κB p105/p50 caused by inflammation.Conclusion: The anti-inflammatation effect of etanercept may be related to its activity in inhibiting the activation of TNF-α/NF-κB pathway.

Key words: etanercept, rheumatoid arthritis, TNF-α/NF-κB pathway, rats