人类神经前体细胞大鼠胎脑内移植研究

Intraventricular Transplantation of Human Neural Stem Cells into Embryonic Rats

目的探讨人类神经前体细胞大鼠胎脑侧脑室内移植后的移行和分布.方法采用机械方法从胎脑中分离神经细胞,应用N2培养基进行培养,细胞用携带LacZ基因的腺病毒或BrdU标记,移植到孕期为16～18 d的胎鼠侧脑室内,检查出生后不同时期脑组织中移植细胞的分布和移行.结果成功培养出人类的神经干细胞,细胞聚集形成神经球,呈悬浮状态,大部分细胞表达神经前体细胞的标志物巢蛋白,这种细胞能够分化为神经元、星型胶质细胞和少突胶质细胞.神经干细胞在体内和体外可以稳定表达外源性基因,移植到胎鼠脑内,人类胚胎神经前体细胞广泛移行并分布于宿主的脑组织中,结合到大鼠的前脑、中脑和后脑,形成广泛的嵌合现象. 结论神经干细胞可以稳定表达外源性基因,移植到发育期的脑内,能够整合到脑组织中,形成广泛的嵌合现象.

Objective To explore the migration and distribution of human neural stem cells （NSCs） after they were transplanted into lateral cerebroventricles of embryonic rats. Methods This study was conducted with the proxy consent and the permission from the Hospitals Ethical Review Committee. The cells from the embryonic human cortices were mechanically dissociated. N2 medium was used to culture and expand the cells. And the cells were identified by immunocytochemistry; then after being labelled with BrdU or adenovirus carrying LacZ gene, they were implanted into the lateral cerebroventricles of embryonic rats. The rats were sacrificed after they were born and the brain sections were examined by immunocytochemistry at different time points. Results NSCs from embryonic humans were successfully cultured; they formed typical neurospheres in suspension, and the majorities of the cells expressed nestin, which was the marker for neural progenitor cells, and the cells could differentiate into neurons, astrocytes and oligodendrocytes. NSCs could steadily expressed exogenous gene in vivo and in vitro; after transplantation into embryonic rat brains, the fetal human NSCs incorporated individually into all major compartments of the brains, generating widespread CNS chimerism and having a wide distribution in the host fore-, mid-, and hindbrain. Conclusion NSCs could express foreign gene steadily and were the ideal cell sources for cell and gene therapy. These cells could incorporate into developing brains and generate widespread chimerism. These chimeras provide a unique model for studying human neural cell migration and differentiation in a functional nervous system.