Morphological and molecular cell biological study of apoptosis in mammalian morphogenesis

1.采用尼罗蓝-硫酸盐染色方法，连续检测妊娠第11-15天小鼠胚胎肢体发育过程中的细胞凋亡。研究发现，在指间充质形成过程中，程序性细胞死亡(PCD)始于指间充质的近端，随后向远端扩展。因此，发生在指间区的初始PCD可以决定指骨分离的近端，也有助于手掌(鞋底)和脚趾(脚趾)之间的分界。在指分离过程中，指间区PCD的面积在第13天变大并向远端扩张，这可能是分离指和确定指间区消失所必需的。此外，在手板和足板的胫骨和尺骨边缘观察到强烈的PCD，持续4-5天。边缘区域的这种PCD似乎阻止了额外数字的形成(前后轴Polydac…更多的泰利)和其他数字畸形。HSP105(105k-Da热休克蛋白)在妊娠第8天小鼠胚胎中检测到少量细胞，但从第9天到第11天其水平显著升高，到第14天时逐渐下降。HSP105定位于致密细胞和致密小体，呈典型的指间区细胞凋亡特征。这些发现表明，HSP105在小鼠胚胎发育过程中起着重要作用。用DNA缺口末端标记法、透射电子显微镜和电泳法观察了丝裂霉素C(MMC)对成年雄性小鼠生精细胞凋亡的影响。结果发现，在MMC处理的小鼠睾丸中，(1)MMC诱导的凋亡细胞呈剂量依赖性；(2)精原细胞最常见，精母细胞次之；(3)MMC诱导的凋亡细胞死亡不是生精小管的特异性。提示MMC的睾丸毒性可能与其诱导生精细胞凋亡有关。较少

1. Apoptotic cell death in the developing limb of mouse fetuses was examined sequentially on days 11-15 of gestation by means of Nile blue sulfate staining. It was found that during digit formation, programd cell death (PCD) begins at the proximal portion of the interdigital mesenchyme and subsequently expands distally. Therefore, the initial PCD that occurs in the interdigital zones may determine the proximal ends of digital separation and also contribute to the demarcation between the palm (sole) and digits (toes). During digit separation, the areas of PCD in the interdigital zones were found to become larger and expand distally on day 13, which may be necessary for the separtion of digits and for determining the the interdigital area to disappear.In addition, intense PCD was observed in the radila (tibial) and ulnar (fibular) margins of the hand and foot plates for 4-5 days. Such PCD at marginal areas seems to prevent the formation of supernumerary digits (pre-and poistaxial polydac … More tyly) and other digital malformations.2. HSP105 (105 k-Da heat shock protein) was detected scarcelyt in mouse embryos at gestational day (GD) 8, but its level increased markedly from GD9 to 11 and then decreased gradually by GD14. HSP105 was found to be localized in condensed cells and condensed bodies showing the typical characteristics of apoptosis at the interdigital region of the limb.. These findings suggest that HSP105 plays important roles during mouse embryo development.3. Mouse spermatogenic cell apoptosis was examined in mature male mice after administration of mitomycin C (MMC) using DNA nick end labeling, transmission electron microscopy (TEM) and electrophoresis. It was found tha in the testis of MMC-treated mice, (1) apoptotic cell treated with DNA feagmentation is induced by MMC dose-dependently, (2) apoptotic cell death was found to occur most commonly in spermatogonia and less frequently in spermatocytes, and (3) apoptotis cell death induced by MMC was not specific for the seminiferous stage of the tubules. It is suggested that spermatogenic cell apoptosis induced by MMC might be involved in its testicular toxicity. Less