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 dea th in chondrocytes of the growth plate. In the degenerative chondrocyt e zone of the growth plate, apoptotic chondrocytes were defeated by th e in situ nick end labelling method, by DNA analysis in agarose gel, a nd by electron microscopy. The results of the in situ nick end labelli ng method and the occurrence of a ladder pattern of DNA in agarose gel analysis indicated the activation of endogenous endonucleases, result ing in DNA fragmentation. Electron micrographs showed the early morpho logical changes associated with apoptosis. This report presents both m orphological and biochemical evidence for apoptosis in the terminal hy pertrophic chondrocytes of the growth plate. These data suggest that a poptosis of degenerative chondrocytes may play an important role in th e control of normal and pathological endochondral ossification.