Garcia-Martinez V, Macias D, Gañan Y, Garcia-Lobo J M, Francia M V, Fernandez-Teran M A, Hurle J M
Dpto. Ciencias Morfológicas, Universidad de Extremadura, Badajoz, Spain.
J Cell Sci. 1993 Sep;106 ( Pt 1):201-8. doi: 10.1242/jcs.106.1.201.
In this work we have attempted to characterize the programmed cell death process in the chick embryonic interdigital tissue. Interdigital cell death is a prominent phenomenon during limb development and has the role of sculpturing the digits. Morphological changes in the regressing interdigital tissue studied by light, transmission and scanning electron microscopy were correlated with the occurrence of internucleosomal DNA fragmentation, evaluated using agarose gels. Programming of the cell death process was also analyzed by testing the chondrogenic potential of the interdigital mesenchyme, in high density cultures. Our results reveal a progressive loss of the chondrogenic potential of the interdigital mesenchyme, detectable 36 hours before the onset of the degenerative process. Internucleosomal DNA fragmentation was only detected concomitant with the appearance of cells dying with the morphology of apoptosis, but unspecific DNA fragmentation was also present at the same time. This unspecific DNA fragmentation was explained by a precocious activation of the phagocytic removal of the dying cells, confirmed in the tissue sections. From our observations it is suggested that programming of cell death involves changes before endonuclease activation. Further, cell surface changes involved in the phagocytic uptake of the dying cells appear to be as precocious as endonuclease activation.
在这项工作中，我们试图描述鸡胚趾间组织中的程序性细胞死亡过程。趾间细胞死亡是肢体发育过程中的一个显著现象，具有塑造指（趾）的作用。通过光镜、透射电镜和扫描电镜研究退化的趾间组织中的形态学变化，并与使用琼脂糖凝胶评估的核小体间DNA片段化的发生情况相关联。还通过在高密度培养中测试趾间间充质的软骨形成潜力来分析细胞死亡过程的编程。我们的结果显示，趾间间充质的软骨形成潜力逐渐丧失，在退化过程开始前36小时即可检测到。仅在出现具有凋亡形态的死亡细胞时才检测到核小体间DNA片段化，但同时也存在非特异性DNA片段化。这种非特异性DNA片段化是由对死亡细胞的吞噬清除的早熟激活所解释的，这在组织切片中得到了证实。根据我们的观察结果表明，细胞死亡的编程涉及内切核酸酶激活之前的变化。此外，参与吞噬死亡细胞的细胞表面变化似乎与内切核酸酶激活一样早熟。
