To study the characteristics of apoptosis in the condyles of osteoarthritic temporomandibular joints, and investigate its role in the pathogenesis of the disease.
Temporomandibular joint osteoarthrosis model of rabbits was created by partial resection of joint disc. The animal models were sacrificed in the 15th day, the 1st month, the 2nd month, the 3rd month, the 4th month, the 5th month, and the 6th month chronologically. Then the pathological condyles were sectioned and detected with TUNEL method to investigate the apoptosis within the tissue.
In the reactive repairing state of osteoarthrosis, 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 loss of articular cartilage, the phenomena of apoptosis decreased in the lower zone of cartilage and increased in the hypertrophic and calcified zone.
There were abundant phenomena of apoptosis within the condylar cartilage of osteoarthritic temporomandibular joint. Abnormal proliferation and abundant apoptosis would disturb the regulation mechanism in the cartilage matrix and lead to the osteoarthrosis.