Effects of chondrocyte apoptosis and IL-1β、TNF-α under compressive stress

Objective:To investigate the histologic changes of articular cartilage and the apoptosis of chondrocyte under continuous or intermittent compressive stress. To explore the relationship between chondrocyte apoptosis and the degeneration of cartilage,the possible mechanism of chondrocyte apoptosis under compressive stress. Method: Different continuous and intermittent compressive press model were designed between the patella and femur. 58 New Zealand white rabbits were randomly grouped into 7:group A:control group: group B:continuous straight; group C: continuous bend 80°; group D:continuous bend 140°;B1 group:intermittent straight;C1 group:intermittent bend 80°;D1 group:intermittent bend 140°. Continuous groups were killed at the time of 1week?2week?4week?8week,intermittent groups were killed at the time of 4week?8week?12week. Before killing,the compressive press between the patella and femur was firstly measured.The histologic changes of cartilage were investigated. The apoptosis of chondrocyte was detected. The amount of cytokines was analysed through ELISA method. Result:The higher compressive stress can induce the apoptosis of chondrocyte,then lead to the degeneration of cartilage. The amount of cytokine in synovial fluid also increased at the same time. The changes under the continuous compressive stress were more. The long period immobilization could induce the same changes. Conclusion:The higher compressive stress can induce the apoptosis of chondrocyte and lead to the degeneration of cartilage. IL-1β and TNF-α may play an important role in the apoptosis of chondrocyte.