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目的:研究并分析神经干细胞的超微结构和生物学特征。方法:无血清培养大鼠胚胎中脑组织中神经干细胞,用血清诱导分化。扫描及透射电镜观察神经球及单个神经干/祖细胞的超微结构。结果:培养的神经干/祖细胞呈神经球样生长,经血清诱导可分化为神经元样和神经胶质细胞样细胞。扫描电镜下神经球表面的细胞直径约为5～10μm,常3～5个以上彼此粘附聚集成簇,松散不规则分布。透射电镜下神经球由神经干细胞和无定形结构的物质构成,根据电子密度不同分为明细胞和暗细胞。神经球内部大部分相邻细胞排列紧密,部分细胞可见有贯通两相邻细胞膜的通道;少部分相邻细胞排列疏松,并见部分相邻细胞间有壁呈腺泡样结构的囊泡的释放活动。神经球内干/祖细胞核质比高,多种细胞器不发达,高尔基复合体、核糖体、溶酶体等在不同神经干/祖细胞中的数量和分布不一致。多见自噬小体,髓样体。大部分细胞为单核,罕见双核、肾形核,常染色质多分布均匀,异染色质少,多见单个核仁。结论:胚鼠中脑神经干/祖细胞球内紧密排列的相邻细胞间有贯通两胞膜的孔道,排列疏松的相邻细胞间有腺泡样结构的囊泡的释放活动。研究结果为进一步研究多因子对神经干/祖细胞的发育增殖、定向分化的调控及其相关途径奠定了一定基础。
Objective: To study and analyze the ultrastructure and biological characteristics of neural stem cells. Methods: Neural stem cells in rat embryonic midbrain tissue were cultured in serum-free medium and induced by serum. Scanning and transmission electron microscopy were used to observe the ultrastructure of neurospheres and single neural stem / progenitor cells. Results: The cultured neural stem / progenitor cells showed neurosphere-like growth and were differentiated into neuron-like and glial-like cells by serum induction. Under the scanning electron microscope, the diameter of the surface of the neurospheres is about 5 ~ 10μm, and more than 3 ~ 5 of them adhere to each other and form clusters, loosely and irregularly distributed. Under the transmission electron microscope, the neurospheres are composed of neural stem cells and amorphous structures, and are divided into bright cells and dark cells according to their electron density. Most of the adjacent neurospheres within the close arrangement of cells, some cells can be seen through two adjacent cell membrane channels; a small number of adjacent cells loosely arranged, and see some of the adjacent cells wall acinar-like structure of the release of vesicles activity. The ratio of nuclear and cytoplasm in neurosphere and progenitor cells is high, and many organelles are underdeveloped. The quantity and distribution of Golgi complex, ribosome, lysosome and so on in different neural stem / progenitor cells are inconsistent. More common body of autophagy, medullary body. Most of the cells are mononuclear, rare dual nuclei, kidney nuclei, euchromatin and more evenly distributed, less heterochromatin, more common single nucleolus. CONCLUSION: There are channels between the adjacent cells in the midbrain neural stem / progenitor cells of the embryonic rat that are closely arranged in the two membranes, and loosely arranged adjacent cells with acinar-like vesicles. The results lay a solid foundation for further research on the multifactorial regulation of neural stem / progenitor cell proliferation and differentiation and its related pathways.