神经干细胞及其在脑修复中的可能应用

成年哺乳动物脑内存在有能分化成神经元或神经胶质的神经干细胞，这种神经前体细胞一般位于脑室壁部位。从胎脑分离下来的神经前体细胞能在体外分裂并进一步分化成神经元和胶质细胞，许多包括生长因子在内的活性物质或分子结构参与这一分化过程并决定这些细胞的转归；从成年脑中也能分离出有繁殖能力的细胞，当这些存在于中枢神经系统内的干细胞（即多潜能细胞）和具有明确前景的前体细胞（神经母细胞和胶质母细胞）遇到与胚胎时期相同因子的影响时也会分裂、分化。由于在体外培养状况下难以提供神经前体细胞分化繁殖的所有条件，故将其植入发育中或成年中枢神经系统特定部位的做法是研究神经干细胞特性，特别是研究决定其分化微环境的有效办法。对神经干细胞的研究，为进一步探讨神经元的发生、迁移、分化和诊治多种神经疾患提供了新的机遇。

THE NEURAL STEM CELLS AND THEIR POTENTIAL USAGE FOR BRAIN REPAIR

There are a certain number of neural stem cells,which can be potentially differentiated into the neurons or neuroglia,in the adult mammalian brain.These neural precursors are located in the subependymal cell layer of the ventricle.Those precursors isolated from embryonic brain can be divided and differentiated into the neurons and glia in vitro and this is regulated by a series of growth factor actions.The neural precursors with the ability of proliferation are also isolated from adult brain.The neural stem cells(multipotent precursors) and the progenitor cells (neuroblasts and glioblasts) are also divided and differentiated when they meet the same factors as in the embryo.The neural stem cells can be characterized,especially for their microenvironment of differentiation,by transplanting them into certain parts of adult or embryonic brain,since the real conditions for proliferation of those stem cells in vivo are provided with difficulties in vitro . The use of neural stem cells may bring us a favorable opportunity for exploring neuronal generation,migration and differentiation,as well as the effective CNS repair.