Morphological and molecular cell biological study of apoptosis in mammalian morphogenesis

1.在妊娠第11-15天，通过Nile蓝硫酸盐染色，依次检查小鼠胚胎发育肢体中的细胞凋亡。结果发现，在手指的形成，程序性细胞死亡（PCD）开始在近端部分的趾间充质，随后扩大远端。因此，发生在指间区的初始PCD可以确定手指分离的近端，并且还有助于手掌（脚底）和手指（脚趾）之间的分界。在手指分离过程中，第13天趾间区的PCD面积变大并向远端扩展，这可能是手指分离和确定趾间区消失所必需的，此外，在4-5天的时间里，手和足板的桡骨（胫骨）和尺（腓骨）边缘观察到强烈的PCD。这种边缘区域的PCD似乎可以防止多指（轴前和轴后多指）的形成 关于我们 tyly）和其他数字畸形。HSP 105（105 k-Da热休克蛋白）在妊娠第8天（GD）小鼠胚胎中的表达量很少，但在GD 9 ~ 11天显著升高，到GD 14天逐渐下降。HSP 105定位于凝聚细胞和凝聚体中，显示出肢体趾间区典型的凋亡特征。提示HSP 105在小鼠胚胎发育过程中起重要作用.应用DNA缺口末端标记、透射电镜和电泳技术研究了丝裂霉素C（MMC）对小鼠生精细胞凋亡的影响。结果表明：（1）MMC剂量依赖性地诱导睾丸细胞凋亡;（2）MMC诱导的睾丸细胞凋亡主要发生在精原细胞，其次是精母细胞;（3）MMC诱导的睾丸曲细精管细胞凋亡并不特异于曲细精管。提示MMC的睾丸毒性可能与其诱导生精细胞凋亡有关。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