微小RNA-155和脑源性神经生长因子在砷对PC12细胞损伤中的表达及意义

Expression and significance of microRNA-155 and BDNF in PC12 cells damage exposed to sodium arsenite

目的探讨微小RNA-155(miR-155)和脑源性神经营养因子(BDNF)在砷对PC12细胞损伤中的作用及机制。方法培养大鼠肾上腺嗜铬细胞瘤12(PC12)细胞株,将细胞分为对照组和2.5、5、10、20μmol/L NaAsO_(2)染毒组;MTT检测细胞存活率,电镜观察各组细胞的超微结构,实时荧光定量PCR(RT-qPCR)检测miR-155和BDNF mRNA表达,蛋白印迹(Western blot)检测BDNF蛋白的表达。结果电镜下发现各染毒组出现不同程度的细胞器损伤;与对照组比较,NaAsO_(2)各染毒组(除2.5μmol/L组外)随染毒剂量的增加,PC12细胞存活率逐渐下降(P<0.05)、miR-155的表达量逐渐增加(P<0.05)、BDNF mRNA和蛋白表达量逐渐降低(P<0.05)。结论NaAsO_(2)对PC12细胞有直接毒性作用,miR-155及BDNF表达水平随染砷浓度增加而改变,其可能是致PC12细胞损伤的机制。

Objective To investigate the effect and expression of miR-155 and brain-derived neurotrophic factor(BDNF)in arsenic-stained PC12 cells.Methods The cell lines of Rat pheochromocytoma cells(PC12)were cultured and exposed to NaAsO_(2)(0,2.5,5,10,20μmol/L)at different concentrations for 24 h.The cell survival rate was analyzed.Expressions of mir-155 and BDNF were detected by RT-qPCR and BDNF were detected by Western blot.Results Compared with the control group,the survival rate of PC12 cells of all the sodium arsenite poisoning groups decreased with the increase of the dose of exposure(P<0.05),except for the 2.5μmol/L group.Under electron microscope,organelle damages of different degrees were found in the arsenic group.The expression of miR-155 increased with the increase of arsenic concentration(P<0.05).RT-qPCR and Western-blot analysis showed that the mRNA and protein expression of BDNF gradually decreased with the increase of arsenic concentration(P<0.05).Conclusion Sodium arsenite has a direct toxic effect on PC12 cells,resulting in decreased activities of normal cells.The expression of BDNF decreases with the increase of arsenic concentration,while the expression of miR-155 increases and shows a dose-effect relationship.