人胚胎海马发育的形态学研究──Ⅱ．神经细胞与神经胶质细胞的分化

利用Ｈ－Ｅ和Ｎｉｓｓｌ染色法、免疫细胞化学法、Ｇｏｌｇｉ镀银法及透射电镜技术，对６０例６周至足月人胚胎海马神经细胞及神经胶质细胞的分化、发育进行了观察。结果表明；神经细胞及神经胶质细胞均由未分化细胞转化而来。未分化细胞、神经细胞和神经胶质细胞在对硝酸银的嗜染性、免疫细胞化学特征及超微结构特征等方面都有显著差别。神经细胞为神经元特异性烯醇化酶（ＮＳＥ）阳性细胞，主要有锥体细胞、颗粒细胞和篮状细胞等。星形胶质细胞和放射状胶质细胞为胶质原纤维酸性蛋白（ＧＦＡＰ）阳性细胞。未分化细胞体积小、球形、胞质少，为ＮＳＥ及ＧＦＡＰ阴性，硝酸银镀染也不着色；透射电镜下未分化细胞核异染色质丰富，胞质内缺乏特化的细胞器，但糖原含量丰富。胚胎早期室管膜神经上皮细胞及由此迁徙而来的中间层细胞均由未分化细胞构成。星状胶质细胞和放射状胶质细胞出现较早，第１１周开始出现于室管膜下的室床及海马伞部；随胎龄增加，单位面积垦状胶质细胞数量增加，１７周后维持在相对稳定状态，并且均匀分布于海马各个部位与区域。１５周后中间层细胞陆续开始分化为锥体细胞和颗粒细胞，到足月胚胎锥体层及颗粒层不再有未分化细胞。

A MORPHOLOGIC STUDY OF HUMAN FETAL HIPPOCAMPAL DEVELOPMENT Ⅱ.THE DIFFERENTIATION OF NERVE CELLS AND GLIAL CELLS

With H-E stain, Nissl stain,Golgi method, immunocytochemical methods and transmission electron microscope,the differentiation of hippocampal nerve cells and glial cells of 60 cases from 6th week to full term fetuses was studied.The results showed: both nerve cells and glial cells were derived from undifferentiated cells.The undifferentiated cells, nerve cells and glial cells showed remarkable difference in their silvering,immunocytochemical and ultrastructural character. Nerve cells were neuron specific enolase(NSE)positive cells.They were mainly pyramidal cells, granular cells and basket cells.The astrocytes and radial glial cells were GFAP positive cells.The undifferentiated cells were small, global,with little cytoplasm,and belonged to NSE and GFAP negative cells.Under electron microscope,the undifferentiated cells were rich in glycogen, with little special organelles.The early fetal ependymal neuroepithelial cells and cells in the intermediate lamina that migrated from the ependyma were all undifferentiated cells.Astrocytes and radial glial cells appeared first in oriens and fimbria in 11th week.With increasing fetal age, they were increasing in number and distributed evenly in the hippocampus.By 15th week, the cells of intermediate lamina began to differentiate into pyramidal cells and granular cells.At full term no undifferentiated cells could be found in the pyramidal and granular lamina.