Ghanem E, Cornelissen M, Thierens H, De Ridder L
Department of Anatomy, Embryology and Histology, University of Gent, Belgium.
Experientia. 1996 Jul 15;52(7):683-6. doi: 10.1007/BF01925574.
To study the possible mechanism of the age-dependent involution of the notochord, isolated mesenchyme-free notochords of chick embryos were cultured in vitro and compared with their counterparts in vivo. Two different aspects were evaluated: (1) DNA synthesis measured by [3H]thymidine incorporation and visualized by autoradiography and (2) cell death quantified by counting the number of pyknotic nuclei. The results demonstrate that [3H]thymidine uptake by notochords shows an age-dependent decrease in vitro as well as in vivo. The number of [3H]thymidine-labelled notochord cells, however, is higher in vitro than in vivo. At the same time, there is an age-dependent increase in pyknosis in the notochord in vivo and in vitro. So, during the aging process, the number of both pyknotic nuclei and of [3H]thymidine-labelled nuclei suggest a high turnover of notochord cells in vitro. From these results, we can conclude that the process of involution in aging notochord seems to be controlled by a programmed intrinsic process, which might be influenced partially by the microenvironment in vivo.
为研究脊索随年龄退化的可能机制，将鸡胚中分离出的无间充质脊索进行体外培养，并与体内的对应物进行比较。评估了两个不同方面：（1）通过[3H]胸苷掺入法测定并通过放射自显影观察DNA合成；（2）通过计数固缩核的数量来量化细胞死亡。结果表明，脊索对[3H]胸苷的摄取在体外和体内均呈现出随年龄增长而下降的趋势。然而，[3H]胸苷标记的脊索细胞数量在体外高于体内。同时，体内和体外脊索中的固缩现象均随年龄增长而增加。因此，在衰老过程中，固缩核和[3H]胸苷标记核的数量表明体外脊索细胞的更新率很高。从这些结果可以得出结论，衰老脊索的退化过程似乎受程序性内在过程控制，该过程可能部分受体内微环境的影响。
