CHONDROCYTE APOPTOSIS IN DEVELOPMENT, AGING AND DISEASE

There is increasing evidence that chondrocyte apoptosis plays an impor tant role in cartilage development, aging and disease. A variety of mo rphological and biochemical studies have identified apoptotic chondroc ytes in both growth plate and articular cartilage of a variety of spec ies. In addition, there is an ever increasing list of diverse stimuli that can induce chondrocyte apoptosis in vitro. A feedback loop regula ting chondrocyte apoptosis in the growth plate has been described that includes Indian Hedgehog, parathyroid hormone-related protein and Bcl -2. The molecular mechanism regulating apoptosis in articular cartilag e is still under investigation. Future studies should elucidate more f ully how abnormal regulation of chondrocyte apoptosis may contribute t o the development of chondrodysplasias and chondrosarcomas. Also, it w ill be of importance to define the relationship between chondrocyte ap optosis and the regulation of chondrocyte-specific gene expression.