Abstract: Abstract：　Objective　 The purpose of this study was to establish a mechanical-stress-induced OA model of the rat TMJ. Methods　 Six-week-old female SD rats were divided into control group and OA group at random. Each group had 5 rats. Passive mouth opening (3h/day, last for 5 days) was used to build up the TMJOA animal model. Toluidine blue staining and collagen II immunohistochemical staining were used to analyze the structural change of condyle cartilage. Micro-ct was used to evaluate the subchondral bone remodeling.Results　 Expression of proteoglycan and collagen II decreased in cartilage and bone mineral density (BMD) of subchondral bone decreased in OA group. Conclusions　 Forced jaw opening without surgical intervention can induce evident OA-like lesions in the rat TMJ, and this OA model may contribute to the elucidation of the cartilage degradation mechanism in TMJ OA.

Key words: forced-mouth-opening, Temporomandibular joint osteoarthritis-like lesion, animal model