OBJECTIVETo prove the therapeutic effects of Sihuang powder (composed by four traditional Chinese herbs: root of baikal skullcap, bark of amur corktree, root of sorrel rhubarb, fruit of cape jasmine, which were mixed with wild Chrysanthemum flower solution)in treating acute synovitis in experimental rabbit knee osteoarthritic models induced by papain injection and to explore its mechanism.

METHODSThirty-two New-Zealand white rabbits were divided into 6 groups: blank group, model group, Sihuang powder with high dosage group (2 g/kg), Sihuang powder with low dosage group (1 g/kg), Yingtaiqing group and wild Chrysanthemum flower group. The latter four groups were treated respectively with low and high dose Sihuang powder synovium and cartilage were tested concentrations of nitrogen monoxide (NO) and IL-1 level and then were prepared for pathologic and histologic observation 10 days later. Cartilage pathologic changes were record and synovium pathologic changes were valued by means of Mankin's value system.

RESULTSThe NO concentration of synovium in Sihuang powder with high dosage group was lower than that of model group, and there was significantly differences between the two groups (P < 0.01). The IL-1 level of synovium was failed after treated with Sihuang powder with high dosage (P < 0.05). Sihuang powder with low dosage and Yingtaiqing also could restrain IL-1's release (P < 0.05). In Mankin's value system, Sihuang powder with high dosage almost eliminated inflammatory cells infiltrating in synovium, which was seldom found in other groups. The value of Sihuang powder with high dosage group was the lowest in treatment groups (P < 0.005). Sihuang powder with low dosage group and wild Chrysanthemum flower group also decreased the degree of inflammatory in synovium (P < 0.05).

CONCLUSIONSihuang powder can reduce the concentration of NO and IL-1 and improve inflammatory cell infiltrate in lining cells of synovium. Moreover, it can alleviate swelling and pain of joint, improve joint movement and postpone degeneration of the cartilage.