ABSTRACT
<b>Objective::To observe the effect of Youguiwan on the levels of cartilage transducers and activators of transcription 3 (STAT3) and interleukin-6 (IL-6) in rats with knee osteoarthritis (KOA). <b>Method::Sixty SD rats were randomly divided into six groups: sham control group, model group, glucosamine sulfate group and Youguiwan (high, middle and low-dose) groups. The modified Hulth method was used to prepare KOA models for 6 weeks. The shame control group and the model group were treated with normal saline, Youguiwan high, middle, low-dose groups received Youguiwan 4.8, 2.4, 1.2 g·kg<sup>-1</sup> by gavage respectively, and the glucosamine sulfate group was treated with glucosamine sulfate 0.17 g·kg<sup>-1</sup>. The rats were administrated for 8 weeks according to the dose. After intervention, each group was put to death by femoral artery blood collection, and the keen cartilages of the rats were collected. The pathological changes were observed by htoxylin eosin (HE) staining method, and Mankin score was evaluated. The expressions of STAT3, superoxide dismutase3(SOD3) and Wnt inhibitory factor 1(WIF1) in articular cartilage were detected by immunohistochemistry. The expressions of IL-6 mRNA in articular cartilage were detected by quantitative real-time fluorescence polymerase chain reaction (Real-time PCR). The expression of WIF1 in articular cartilage was detected by Western blot. <b>Result::Compared with the sham control group, the Makin score was obviously increased in the model group, the protein expression of STAT3 was increased significantly, the mRNA of IL-6 was raised significantly, but the protein expression of WIF1 was decreased significantly (<italic>P</italic><0.01), articular cartilage was seriously damaged, and chondrocytes were arranged in disorder. Compared with the model group, the Makin score was declined obviously in the high-dose Youguiwan group, the protein expression of STAT3 was significantly reduced, the mRNA expression of IL-6 was significantly reduced in Youguiwan treatment group, while the protein expression of WIF1 was significantly increased (<italic>P</italic><0.05, <italic>P</italic><0.01), the cartilage structure returned to be normal, the chondrocytes distribution was uneven, and articular cartilage surface was not smooth. <b>Conclusion::Youguiwan could significantly improve the articular cartilage degeneration of KOA rats, and inhibit the inflammation of chondrocytes, which may be related to the suppression of STAT3 and IL-6 expression.