Abstract: AimTo study the effects of TNF receptor blocking peptide on adjuvant arthritis in rats. MethodsThe model of rat adjuvant arthritis was induced by injection of complete Freund's adjuvant. The TNF receptor blocking peptide was injected locally in the ankle. The ankle swelling, the pathologic changes in the ankle joint and the expression of IL-1β mRNA and TNF-α mRNA by peritoneal macrophages (RT-PCR) were observed. ResultsThe model of rat adjuvant arthritis induced by injection of complete Freund's adjuvant was similar to human rheumatoid arthritis. The treatment with TNF receptor blocking peptide for 10 days resulted in complete inhibition of joint swelling, a decrease in infiltration of inflammatory cell into joint tissue, an obvious alleviation of inflammatory pathological damages and an apparent decline of TNF-α mRNA and IL-1β mRNA of peritoneal macrophages of rats. ConclusionThe TNF receptor blocking peptide can protect the joint from inflammatory damage induced by adjuvant arthritis by suppression of TNF-α and IL-1 production, thereby alleviating the pathological injury of joint and controlling effectively the clinic course of arthritis.