Comparison and applicability of three induction methods of temporomandibular joint osteoarthritis in murine models

Background Temporomandibular joint osteoarthritis (TMJ‐OA) causes severe symptoms such as chewing difficulties, acute pain and even maxillofacial deformity. However, there is hardly any effective disease‐curing strategy because of uncertainty in aetiology. Animal model is an excellent tool to investigate the mechanism, prevention and treatment on diseases. Currently, although several TMJ‐OA animal models have been established, there are almost no comparative studies on different models, which poses a great challenge for selecting suitable models. Objective To compare three TMJ‐OA induction methods and assess their applicability considering pathological changes in the cartilage, subchondral bone, osteoclasts, and synovium. Methods Murine models were employed and followed for 3 and 6 weeks after experimental procedures (surgery, injection, crossbite). The TMJ changes were evaluated by Safranin‐O/Fast green staining, immunofluorescence staining, micro‐CT, TRAP staining, and HE staining. Results In the Surgery group, a pronounced drop in bone volume fraction was observed. In the Injection group, chondrocytes were mostly disordered or arranged in clusters and a substantial increase in the OARSI score and osteoclasts was found. The OARSI score and osteoclasts also increased significantly in the Crossbite group, although to a lower extent compared with injection. Conclusion Osteoarthritis‐like changes were observed in all models. Concerning the applicability of the different induction methods, surgery might be an important resource for the assessment of post‐traumatic TMJ‐OA and subchondral bone changes in early stages. Injection induces a severe end‐stage osteoarthritis in a short time and provides model basis for advanced TMJ‐OA. Crossbite might be more reasonable model to explore the pathogenesis mechanism of temporomandibular arthritis due to occlusal disorders.