NGF和GDNF基因重组逆转录病毒体外感染神经干细胞及其鉴定

目的 探讨神经干细胞（NSC）直接作为基因靶细胞能否被重组逆转录病毒感染以及感染后目的基因的表达。方法 分别用NGF和GDNF基因重组逆转录病毒上清液感染NSC2d;G418筛选后加入bFGF扩增培养;取感染后的NSC培养液（NGF／GDNF条件培养液）培养PC12细胞和中脑腹侧神经元;用免疫组织化学染色方法检测中脑腹侧多巴胺神经元的形态改变以及感染后NSC对目的基因的表达。结果 经G418筛选后,约50％感染NGF和GDNF基因重组逆转录病毒的NSC呈G418抗性;这些感染后的NSC开始分化,分裂球向四周长出放射状突起,部分细胞沿突起向外迁移生长;感染NGF基因的NSC呈星形,胞体较大,突起较粗,感染GDNF基因的NSC呈梭形,胞体较小,突起较长。经NGF条件培养液培养的PC12细胞,数量增多,突起明显变长。经GDNF条件培养液培养的中脑多巴胺神经元（TH阳性细胞）其胞体亦增大,突起伸长。大部分G418抗性的NSC出现NGF和GDNF免疫染色。结论 神经干细胞可直接作为基因靶细胞,能被NGF和GDNF基因重组逆转录病毒有效感染而表达和分泌有生物学活性的NGF和GDNF。

INFECTION OF NEURAL STEM CELLS WITH RECOMBINANT RETROVIRUSES CONTAINING NGF OR GDNF cDNA AND THEIR IDENTIFICATION

Objective To explore whether the neural stem cells(NSCs) can act directly as a gene target cell which can be infected by the recombinant retrovirus and express the products of exogenous genes after infection. Methods The NSCs were cultured with supernatant containing the recombinant retroviruses with the genes of NGF or GDNF for two days.After screened with G418,the infected NSC were expanded at the present of bFGF in culture.The PC12 cells and the neurons of ventral midbrain of rat were cultured by the medium from the infected NSC,which were called as GDNF|containing conditioned medium NGF or GDNF|containing conditioned medium the morphological changes of the dopamine neurons of the ventral midbrain and expression of exogenous genes of the infected NSCs were detected by immunohistochemistry staining. Results It was estimated that about fifty percent of NSCs via retrovirus|mediated NGF or GDNF gene transduction were G418|resistant.These infected NSCs began to differentiate.Long and radical processes reached out from the sphere of proliferation and the cells migrated towards outside along the processes.The NSC infected with gene of NGF showed an astroid|shape with larger body and processes.The NSC infected with gene of GDNF showed a shuttle|shape with a smaller body and long processes.The PC12 cells increased in the NGF|containing conditioned medium and stretched out long neurites.The dopamine neuron of the ventral midbrain which were immunoreactive for TH also showed a larger body and longer processes in the GDNF|containing conditioned medium.Most of G418|resistant NSCs were immunoreactive for NGF or GDNF. Conclusion NSC can act directly as a gene target cell which not only be infected by the recombinant retrovirus,but also express and secrete the products of exogenous genes.