[Apoptosis of chondrocytes in experimental osteoarthritis]

The right knees of rabbits were immobilized in full extension for up to eight weeks using plaster cast. Specimens of the articular cartilage obtained from tibial plateau were studied by histopathologic and TDT-mediated fluorescein-dUTP nick-end labelling(TUNEL) techniques. The results showed that TUNEL-positive chondrocytes with apoptosis specific morphology were detected on superficial and middle layer of the articular cartilage from one to two weeks after immobilization, and these changes progressed until 4 weeks after immobilization. Six weeks after immobilization, TUNEL-positive chondrocytes were seen through the entire thickness of the articular cartilage. Our findings indicate that apoptosis of chondrocytes could be induced by immobilization and might be responsible for articular cartilage degeneration, and which is one of the pathways involved in the pathophysiological mechanism of osteoarthritis.