Shimada M, Yamano T, Nakamura T, Morikawa Y, Kusunoki T
Pediatr Res. 1977 Jun;11(6):728-32. doi: 10.1203/00006450-197706000-00006.
Thirty pregnant mice were undernourished by providing low protein diets (PM) or providing approximately one-third their normal diets (PCM) for 9 days from the 8th to the 16th day of gestation. Another 15 pregnant mice, which were fed a normal diet, served as the control. On the 16th day of gestation, all animals were injected with a single does of [3H]thymidine and were killed one by one at 1- or 2-hr intervals. Mean litter size was statistically insignificant between the control group and two malnourished groups. There was, however, a significant difference in mean body weight between the control group and two malnourished groups (P less than 0.005). The cerebral cortex at this stage of development consisted of three different layers, i.e., the cortical plate, the migratory zone, and the matrix layer. The width of the cortical plate of the malnourished embryos was significantly smaller (P less than 0.001). There was, however, no significant difference in width of the migratory zone between the control and the malnourished groups. The width of the matrix layer in PM was significantly smaller (P less than 0.001), but that of PCM showed no significant difference from the control (P greater than 0.1). Coronal section of the brains of the embryos were processed for autoradiography. Labeled cells were found almost exclusively at the matrix layer surrounding the lateral ventricels. Labeling index counted in the matrix layer after 1 or 2 hr of [3H]thymidine injection indicated that more than 30% of the cells in this layer were always synthesizing DNA in each group of embryos. The generation times of the matrix cell, precursor of the neurons, in the matrix layer were approximately 18.5 hr in the control and 21.5 hr and 21.8 hr in the malnourished embryos, thus indicating about 3 hr of prolongation in the latter. DNA synthetic time was about 6.5 hr in the control and 7.0 hr and 7.0 hr in the two malnourished groups. The postduplication time was about 2.5 hr in the control and 3.0 hr and 3.5 hr in the malnourished. The preduplication time was about 8.8 hr in the control and 10.6 hr and 10.3 hr in the malnourished.
在妊娠第8天至第16天期间，给30只怀孕小鼠喂食低蛋白饮食（PM组）或约为其正常饮食三分之一的食物（PCM组），使其营养不足。另外15只喂食正常饮食的怀孕小鼠作为对照组。在妊娠第16天，所有动物均注射单剂量的[3H]胸苷，并每隔1或2小时逐一处死。对照组与两个营养不良组之间的平均窝仔数在统计学上无显著差异。然而，对照组与两个营养不良组之间的平均体重存在显著差异（P<0.005）。发育至该阶段的大脑皮层由三个不同的层组成，即皮质板、迁移带和基质层。营养不良胚胎的皮质板宽度显著更小（P<0.001）。然而，对照组与营养不良组之间迁移带的宽度无显著差异。PM组中基质层的宽度显著更小（P<0.001），但PCM组的基质层宽度与对照组相比无显著差异（P>0.1）。对胚胎大脑的冠状切片进行放射自显影处理。标记细胞几乎只在侧脑室周围的基质层中发现。在注射[3H]胸苷1或2小时后，在基质层中计数的标记指数表明，每组胚胎中该层超过30%的细胞一直在合成DNA。基质层中神经元前体基质细胞的世代时间在对照组中约为18.5小时，在营养不良胚胎中为21.5小时和21.8小时，因此表明后者延长了约3小时。DNA合成时间在对照组中约为6.5小时，在两个营养不良组中为7.0小时和7.0小时。复制后时间在对照组中约为2.5小时，在营养不良组中为3.0小时和3.5小时。复制前时间在对照组中约为8.8小时，在营养不良组中为10.6小时和10.3小时。
