Morphological and biochemical evidence for apoptosis in the terminal hypertrophic chondrocytes of the growth plate.

The purpose of this study was to investigate the mechanism of cell death in chondrocytes of the growth plate. In the degenerative chondrocyte zone of the growth plate, apoptotic chondrocytes were defeated by the in situ nick end labelling method, by DNA analysis in agarose gel, and by electron microscopy. The results of the in situ nick end labelling method and the occurrence of a ladder pattern of DNA in agarose gel analysis indicated the activation of endogenous endonucleases, resulting in DNA fragmentation. Electron micrographs showed the early morphological changes associated with apoptosis. This report presents both morphological and biochemical evidence for apoptosis in the terminal hypertrophic chondrocytes of the growth plate. These data suggest that apoptosis of degenerative chondrocytes may play an important role in the control of normal and pathological endochondral ossification.