镉对胎鼠大脑皮质神经细胞凋亡与一氧化氮合酶基因mRNA转录的影响

Effect of cadmium on the apoptosis and mRNA transcription of nitric oxide synthase of cerebral cortical neurons in embryonic rat

为研究镉对胎鼠大脑皮质神经细胞凋亡与一氧化氮合酶基因mRNA转录的影响,用不同浓度醋酸镉(0、5、10、20μmol/L)染毒胎鼠大脑皮质神经细胞12h,流式细胞术检测细胞凋亡率,荧光显微镜观察镉对神经细胞凋亡的形态学影响,实时荧光定量PCR检测神经型一氧化氮合酶(nNOS)、诱导型一氧化氮合酶(iNOS)mRNA的转录水平。结果显示,与对照组相比,各染毒组细胞凋亡率呈现升高趋势;染镉组细胞核皱缩,染色质致密浓染,甚至核碎裂;5、10μmol/L组nNOS mRNA转录水平显著升高(P<0.05或P<0.01),20μmol/L组nNOS转录水平降低至对照组水平;20μmol/L组iNOS mRNA转录水平极显著升高(P<0.01)。结果表明,镉可诱导大脑皮质神经细胞凋亡,并可调节nNOS和iNOS mRNA的转录。

To study the impact of cadmium on apoptosis and mRNA transcription levels of nitric oxide synthase in primary cerebral cortical neurons of embryonic SD rats,the neurons were exposured to cadmium at different concentrations（0,5,10,20 μmol/L） for 12 h.Then,the apoptosis rates were detected by flow cytometry,toxic effect of cadmium on neuron apoptotic morphology were evaluated by the fluorescence microscope,transcription levels of neuronal nitric oxide synthase（nNOS） and inducible nitric oxide synthase（iNOS） mRNA were detected by real-time fluorescent quantitative PCR.In comparison with the control group,the results showed that the apoptosis rates increased,the nucleus crimpled and chromatin condensed,even nucleus disintegrated in the treated groups.Transcription levels of nNOS mRNA increased significantly（P0.05 or P0.01） in 5,10 μmol/L groups and decreased by the level of the control group in 20 μmol/L group,transcription levels of iNOS mRNA increased significantly（P0.01） in 20 μmol/L group.It was concluded that cadmium can promote the apoptosis of cerebral cortical neurons and regulate the transcription of nNOS and iNOS.