中文摘要：

目的：探讨全反式维甲酸体外促神经干细胞分化为神经元过程中DNA甲基转移酶1和乙酰化组蛋白H3的表达变化。方法：0．5、1．0和4μmol／L全反式维甲酸诱导体外培养的鼠胚神经干细胞，免疫荧光检测NeuN和DAPI，计算各组NeuN／DAPI的比值，免疫印迹检测DNA甲基转移酶1以及乙酰化组蛋白H3表达水平。结果：免疫荧光结果显示给药组NeuN／DAPI比值显著高于对照组。药物浓度在1和4μmol／L时，DNA甲基转移酶1表达水平与对照组相比均显著降低，且有剂量依赖性；而在4μmol／L时，组蛋白H3乙酰化水平较对照组有显著增强。结论：全反式维甲酸促进神经干细胞向神经元的分化可能与DNA甲基转移酶1的表达抑制和组蛋白乙酰化水平增加有关。

英文摘要：

Objective： To investigate the expression of DNA methyltransferase 1 （DNMT1） and acetyl-H3 in differentiation from rat neural stem cells （NSC;s） into neurons in vitro induced by all--trans retinoic acid （ATRA）. Methods： 0. 5 μmol/L, 1.0 μmol/L, 4 μmol/L ATRA were employed to induce the differentiation of NSCs. Double immunofluorescence labeling for neuronal nuclei （NeuN） and 4＇, 6-diamidina-2-phenylindole （DAPI）, the ratio of NeuN/DAPI was counted. Western blotting was used to detect the level of DNMT1 and acetyl-H3. Results： Immunofluorescence showed that the ratio of NeuN/DAPI in the administration group was significantly higher than that of the control group. At the concentration of 1.0 μmol/L, 4 μmol/L, the levels of DNMT1 in the drug administration group decreased compared to the control group. At the concentration of 4 tanol/L, there was a significant increase in the levels of acetyl-H3 compared with the control group. Conclusion： The effect of ATRA inducing the neuronal differentiation of NSCs could be associated to the inhibition of DNMT1 and enhancement of acetyl-H3.