Cangxitongbi capsule protects articular cartilage of the knee in rats by regulating ADAMTS-5

BACKGROUND: Knee osteoarthritis (KOA) is a disease with a high incidence in elderly patients and traditional Chinese medicine has a significant effect on the treatment of KOA. Cangxitongbi capsule (CXTB) is a traditional Chinese medicine for KOA treatment and has a remarkable curative effect. The purpose of this article is to investigate the mechanism of CXTB in protecting joint cartilage on KOA rats. METHODS: A total of 30 male Sprague-Dawley rats were randomly assigned into five groups: control group; model group; low-, mid-, and high-dose CXTB groups (17.5, 35, and 70 mg/mL). KOA models were made by modified Hulth method except the control group. After pharmacological administration for 4 weeks, knee articular cartilages were observed by hematoxylin and eosin (HE) staining and evaluated by Mankin score. Western blot and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the concentration of ADAMTS-5. The peripheral blood of the rats was collected to detect content of interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) by enzyme-linked immunosorbent assay (ELISA). RESULTS: The morphological structure of cartilage in the 3 CXTB groups was significantly improved compared with the model group, and the improvement positively correlated with the drug dosage (P<0.05). Compared with the model group, the expression levels of ADAMTS-5 of the 3 CXTB groups was obviously decreased (P<0.05). Furthermore, the upstream targets of ADAMTS-5, including IL-1β and TNF-α were down-regulated in the 3 CXTB groups (P<0.05). CONCLUSIONS: Knee joint cartilage on KOA model rats is protected by CXTB via down-regulation of ADAMTS-5. The upstream targets of ADAMTS-5, IL-1β and TNF-α, were also down-regulated by CXTB.