Objective To study the characteristics of apoptosis in the condyles of osteoarthritic temporomandibular joints, and investigate its role in the pathogenesis of the disease. Methods Temporomandibular joint osteoarthrosis model of rabbits were created by partial resection of joint disc. The animal models~sacrificed in the 15thday, the 1st, the 2ndmonth, the 3thmonth, the 4thmonth, the 5thmonth, and the 6thmonth chronologically. Then the pathological condyles were sectioned and detected with TUNEL method to investigate the apoptosis within the tissue. Results In the reactive repairing state of osteoarthmsis, the apoptosis cells mainly located in the superficial fibrous layer of articular cartilage. With the remodeling of articular cartilage and bone, the apoptosis cells gradually appeared in the proliferating layer, especially in the "clusters of chondrocytes" . Accompanied with the severe damage and lose of articular cartilage, the phenomena of apoptosis decreased in the lower zone of cartilage and increased in the hypertrophic and calcified zone.Conclusion There were abundant phenomena of apoptosis within the condylar car tilage of osteoarthritic temporomandibular joint. Abnormal proliferation and abundant apoptosis would disturb the regulation mecha- nism in the cartilage matrix and lead to the osteoarthrosis.
