人胚神经干细胞的体外培养和超微结构观察

Culture of Brain-Derived Neural Stem Cells from Human Embryos in Vitro and observation of Their Ultrastructure

目的观察体外分离培养的人胚脑神经干细胞的生物学行为和超微结构特征。方法利用无血清培养和单细胞克隆技术从人胚脑组织中分离培养神经干细胞并用血清诱导其分化,应用免疫荧光细胞化学技术对培养细胞及其分化细胞进行鉴定,并分别用扫描电镜和透射电镜观察其超微结构。结果从人胚脑组织分离的细胞群呈悬浮球状生长,具有连续增殖的能力,并可分化为神经元、星形胶质细胞和少突胶质细胞。扫描电镜发现神经干细胞球中的细胞之间连接较为松散,无紧密连接结构;透射电镜发现神经干细胞的胞核巨大,胞浆少,核浆比例较大,胞浆内细胞器简单,以核糖体和内质网居多。结论神经干细胞具有自我更新能力和多向分化潜能,其超微结构显示早期原始幼稚细胞的发育特征。本研究为进一步的神经干细胞基础研究和临床应用奠定了基础。

Objective To observe the biological characteristics and ultrastructure of brain-derived neural stem cells from human embryos cultured in vitro. Methods The neural stem cells were isolated from the brain of human embryos and cultured with serum-free incubation and single cell cloning technique, and induced to differentiate by serum. The cultured and differentiated cells were identified by immunofluorescence technique and their ultrastructures were observed under a scanning electron microscopy and a transmission electron microscopy. Results In the culture fluid, the cells from human embryos brain formed floating typical neurosphe-res. They could continuously proliferate and immigrate. They were able to differentiate into neurons, astrocytes and oligodendrocytes. The conjunction among the cells in the neurosphere were loose and no tight junction was observed under the scanning electron microscopy. Under the transmission electron microscopy, the cellular nucleus was big, the ratio of nucleus to cytoplasm was very high, and the organelle in the cytoplasm was simple. There were a relative lot of ribosome and reticulum in the cytoplasm. Conclusions The neural stem cells possess the ability of self-renewing and potency of differentiating into various cells. Their uhrastructures have the characters of earlier immature original cells. The present study may be helpful to further basic research on the neural stem cells and their clinical application.