Abstract: AIM:To observe the effects of several common used drugs on expression of acid-sensitive ion channels (ASICs) in articular cartilage in rats with adjuvant arthritis (AA), and to explore cartilage protection of different medicines in the treatment of rheumatoid arthritis (RA).METHODS:The rats were randomly divided into the normal group, AA model group, aspirin (15 mg/kg) group, dexamethasone (0.2 mg/kg) group, tripterygium wilfordii (50 mg/kg) group and levamisole (10 mg/kg) group. The AA rat model was induced by a single intradermal injection of 100 μL of Freund's complete adjuvant (CFA) on day 0. The volume of rat hind paw was measured by means of Volume Meter. The secondary inflammation of AA rats appeared on the d 10 after intradermal injection of CFA. Intraperitoneal injection of dexamethasone at this time, other drug groups were gavaged corresponding experimental drugs, and the model group and the normal group were administered with the corresponding capacity of sterile water, lasting for seven days. The morphological changes of synovial membrane was observed by light microscope. The quantitative PCRwas used to detect the ASICs and aggrecan mRNA expression in rat articular cartilage. The immunoblotting analyses was used to detect the ASICs protein expression in rat articular cartilage. The expression of type Ⅱ collagen was measured by immunohistochemical method. RESULTS:It was found that the secondary paw swelling was inhibited significantly in AA rats. Aspirin obviously inhibited the expression of ASICs of articular cartilage cells in AA rats, but the inhibitory effects of other drugs were not obvious. The type II collagen and aggrecan expression of cell matrix of articular cartilage was increased significantly by four kinds of drugs, especially aspirin, in AA rats. CONCLUSION:Aspirin may play a protective role in articular cartilage in AA rats by inhibiting expression of ASICs.

Key words: aspirin, adjuvant arthritis, cartilage, articulation, ion channels