Abstract:

Objective:The aim of this study was to set up an animal model of osteoarthritis (OA) in the rabbit temporomandibular joint (TMJ).Methods:0.3 ml of 1.6% papain solutionwas injected into the upper compartment of each leftTMJ of six Japanese big ear white rabbits, and the same volume of saline was injected into the upper compartment of leftTMJ as control. The rabbitswere sacrificed 2, 4, 6 weeks respectively afterinjections and the TMJ specimenswere pathologically examined.Results:The degenera- tive changes were demonstrated in the TMJs injected with papain,such as thinner articular cartilage, fibrillation and destroyed car- tilage matrix, and inflammation, proliferation, and degeneration of the synovial tissue. All these changes were much worse with prolonged observation time. Some kinds of reparative changes appeared in the sixth week after papain injection.Conclusion: Pathological similarities between papain induced rabbitTMJ osteoarthritis and human TMJ osteoarthritiswere observed. This animal model has good reproducibility and hence can be used for exploring pathogenesis of this disease and selection of treatments for os- teoarthritis of TMJ.

Key words: papain, temporomandibular joint, osteoarthritis, animal model