Sprague Dawley rats at 4 months of age were randomized into three groups: osteoarthritis (OA), kartogenin treatment (KGN), and control. On day 0, all the rats from OA and KGN group were anaesthetized with 2% isoflurane, a medial arthrotomy was performed and the anterior cruciate ligament was transected (ACLT) on the right knee. Postoperatively, 0.03mg/kg buprenorphine hydrochloride was administered by subcutaneous injection and as needed subsequently for pain control. Rats from KGN treatment group received weekly intra-articular injections of 125mM KGN in 50 ml of saline in the ACL transected knee joint.

Human dermal fibroblasts in vitro were treated with various concentrations of kartogenin, with dimethyl sulfoxide (DMSO) serving as the negative control. Real-time reverse-transcription PCT, Western blot, and immunofluorescence analyses were performed to examine the expression of collagen and transforming growth factor beta (TGF-β) signaling pathway.