Abstract: In this study,the effect of Pileostegia viburnoides water extract on the contents of COX₂, NO, iONS in blood and joint fluid of rats with knee osteoarthritis was studied. The SD rats were randomly divided into 5 groups:normal control group,model group,GS-positive group (glucosamine sulfate group), P.Viburnoides middle dose group and P.viburnoides high dose group.The rat model with knee osteoarthritis was built by injecting a mixture of 4% papain solution and 0.3 mol/L cysteine solution (1:1) into the right knee joint of SD rat at the first,3^rd and 7^th days,20 μL at a time.The P.viburnoides middle,high dose groups were intragastrically administrated with 4.62 g/kg and 9.24 g/kg of P.viburnoides water extract.The GS-positive group was intragastrically administrated with 0.133 mg/kg of glucosamine sulfate.The normal control and model groups were intragastricaly administrated with the same volume of distilled water.After 4 weeks treatment,the contents of COX₂,NO,iONS in the blood and joint fluid in P.viburnoides middle and high dose groups were decreased significantly compared with that of model group.In addition,the results showed that P.viburnoides can effectively inhibit the histomorphologic changes of articular cartilage tissue,indirectly protect cartilage cells and stimulate the recovery of damaged cartilage cells. P.viburnoides can effectively inhibit the expression of COX₂,NO,iONS in synovial fluid and it is one of the mechanisms of delaying the degeneration of articular cartilage.

Key words: Pileostegia viburnoides, osteoarthritis, COX₂, NO, iONS, cartilage histomorphology