Adams C S, Horton W E
Laboratory of Biological Chemistry, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA.
Anat Rec. 1998 Apr;250(4):418-25. doi: 10.1002/(SICI)1097-0185(199804)250:4<418::AID-AR4>3.0.CO;2-T.
Apoptosis in vivo has been identified in developing cartilage from embryonic chick sterna and avian and murine growth plates. To date, no evidence exists that chondrocytes in articular cartilage undergo apoptosis.
We examined the distribution of cells demonstrating fragmented DNA in the articular knee cartilage of C57BL/6 mice (aged 11, 18, 24, and 30 months) and Wistar rats (aged 6, 12, and 24 months) using a DNA end-labeling technique.
Control experiments utilizing retinoic acid-induced apoptosis in a chondrocyte cell line, established that DNA end-labeling correlated with DNA ladder formation. In vivo, apoptotic cells were detected in articular cartilage tissue in both species examined. The percentage of apoptotic cells increased significantly (P < 0.05 with age) for all joint surfaces in both species. No significant difference was found between the medial and lateral or femoral and tibial joint surfaces of the knee. Apoptotic cells were observed in both the calcified and uncalcified regions of the articular cartilage of C57 mice. In the rat, only the calcified region of articular cartilage contained apoptotic cells.
These results suggest that apoptosis plays a role in some aspect of maintenance, remodeling, or turnover of mature articular cartilage. In addition, the increase in apoptosis associated with aging could contribute to the greater risk for cartilage degeneration.
在胚胎期鸡胸骨以及禽类和鼠类生长板的软骨发育过程中已发现体内凋亡现象。迄今为止，尚无证据表明关节软骨中的软骨细胞会发生凋亡。
我们运用DNA末端标记技术，检测了C57BL/6小鼠（11、18、24和30月龄）及Wistar大鼠（6、12和24月龄）膝关节软骨中呈现DNA片段化的细胞分布情况。
利用维甲酸诱导软骨细胞系凋亡的对照实验证实，DNA末端标记与DNA梯带形成相关。在体内，在所检测的两个物种的关节软骨组织中均检测到凋亡细胞。两个物种所有关节面的凋亡细胞百分比均随年龄显著增加（P < 0.05）。膝关节的内侧和外侧或股骨和胫骨关节面之间未发现显著差异。在C57小鼠关节软骨的钙化区和非钙化区均观察到凋亡细胞。在大鼠中，仅关节软骨的钙化区含有凋亡细胞。
这些结果表明，凋亡在成熟关节软骨的维持、重塑或更新的某些方面发挥作用。此外，与衰老相关的凋亡增加可能导致软骨退变风险增加。
