全反式维甲酸诱导中脑神经干细胞向多巴胺能神经元分化的作用

目的：观察全反式维甲酸（all-trans retinoic acid,ATRA）体外对大鼠中脑神经干细胞（neural stem cells,NSCs）的诱导分化作用及其可能的分子机制。方法：分离培养孕14～15 d大鼠中脑NSCs,使用1.0μmol/L ATRA诱导1、3、5和7 d,以免疫组织化学染色观察ATRA对NSCs分化为多巴胺能神经元的影响;RT-PCR分析维甲酸（retiadic acid,RA）各受体表达情况。结果：ATRA诱导后多巴胺能神经元特异性酪氨酸羟化酶（TH）染色呈阳性,细胞有多个细长突起,与对照组比较,诱导7 d后多巴胺神经元特异性TH染色阳性细胞率均明显升高（P〈0.01）;各诱导组RA受体βmRNA的表达量均明显升高（P〈0.01）,而且存在时间依赖性。结论：ATRA能显著提高NSCs分化为多巴胺能神经元的比例,同时发现细胞维甲酸A受体（RAR）βmRNA表达增加,RARβ激活可能促进NSCs向多巴胺神经元方向的分化。

Differentiation of midbrain-derived neural stem cells into dopamine neurons induced by alltrans retinoicacid

Objective: To observe the role of all-trans retinoic acid(ATRA) in inducing differentiation of rat midbrain-derived neural stem cells(NSCs) and its possible molecclar mechanism.Methods: Pregnant 14-15 day rats midbrain-derived NSCs were obtained by mechanical isolation and serum-free culture.Neural stem cells were induced by 1μmol/L ATRA on day 1,day 3,day 5 and day 7.The roles of ATRA in inducing the differentiation of NSCs were observed with immunofluorescent staining,and the expression of retinoic acid receptor(RAR) gene was determined with semi-quantitative RT-PCR.Results: After ATRA induction,neural stem cells were positive for tyrosine hydroxylase(TH),the rate of TH-positive cells significantly increased in the ATRA 7-day groups(P <0.01).Compared with the control group,RARβmRNA expression significantly increased in each group(P <0.01).That ATRA could induce the expression of RARβmRNA was a time dependent manner.Conclusion: ATRA can greatly increase the percentage of neurons differentiation from rat embry-onic neural stem cells and up-regulate the expression of RARβmRNA in rat midbrain-derived NSCs.Activation of RARβ may promote the differentiation of NSCs into dopaminergic neurons.