外源性一氧化氮对小鼠神经干细胞增殖的抑制作用

目的: 探讨外源性一氧化氮(NO)对小鼠神经干细胞(NSC)增殖的抑制作用. 方法: 用含表皮生长因子(EGF)的条件培养基原代培养NSC,在培养基中加入不同浓度的硝普钠(SNP)作为NO的体外供体. 24 h后用Griess还原法检测细胞上清液中NO的释放量;取一半细胞进行MTT试验,另一半细胞换成无SNP的条件培养基继续培养24 h,再行MTT试验. 另取经SNP抑制24 h后的NSC进行血清诱导分化试验和免疫组化试验检测其NOS表达. 结果: 24 h后细胞上清液中NO释放量随SNP浓度的增高而增加;MTT试验反映经SNP作用后的NSC活细胞数较对照组明显减少(P<0.01);经SNP作用后的NSC在解除抑制后仍能保持旺盛的增殖能力并能被诱导分化为神经细胞样细胞,这些NSC表达nNOS和eNOS,而不表达iNOS. 结论: 外源性NO对培养状态下的小鼠NSC有抑制作用.

Ectogenic nitric oxide inhibits proliferation of neural stem cells in mice

AIM: To explore the inhibitive effects of ectogenesis nitric oxide (NO) on the proliferation of neural stem cells (NSC) in mice. METHODS: NSCs were cultured in medium containing EGF, and the medium was supplemented with SNP as a donor of NO in vitro . The release of NO from SNP was measured by Griess assay in the medium after 24 h. Half of the cells in the wells were measured by MTT assay. The rest were kept on culturing in medium without SNP and were measured by MTT assay after 24 h. The NSC depressed by SNP for 24 h were induced to differentiate in medium supplemented with serum and were examined by immunohistochemistry to identify the expression of NOS. RESULTS: The release of NO increased along with the enhancement of the concentration of SNP. The amount of living cells in experiment groups decreased compared with the controls as shown by MTT test ( P <0.01). The NSCs still had the ability to proliferate actively and could be induced to differentiate into neuron and glial cells in medium when SNP was removed. The expression of nNOS and eNOS was positive in NSCs depressed by SNP, but the expression of iNOS was negative. CONCLUSION: Ectogenic nitric oxide inhibits the proliferation of mouse NSC in vitro .