Na^(+)通道在锰神经细胞毒性中的作用

Effects of Na^(+)channels in manganese-induced neurocytotoxicity

目的初步探讨Na^(+)通道在锰神经细胞毒性中对γ-氨基丁酸(GABA)的作用。方法SH-SY5Y细胞建立锰暴露模型,并分为空白对照组、0.25 mmol/L MnCl_(2)、0.50 mmol/L MnCl_(2)、1.00 mmol/L MnCl_(2)。河豚毒素(tetrodotoxin,TTX)0.10μmol/L、0.20μmol/L进行干预,MTT法测其细胞存活率、光学显微镜进行形态学观察、蛋白质印迹法检测Na^(+)通道中Nav1.1通道蛋白和GABA的标记酶谷氨酸脱羧酶65(GAD65)蛋白的表达水平。结果MnCl_(2)可抑制细胞增殖,0.25 mmol/L MnCl_(2)、0.50 mmol/L MnCl_(2)、1.00 mmol/L MnCl_(2)均可显著降低细胞存活率,差异均具有统计学意义(P<0.05);TTX可改善锰暴露所致的神经元损伤,提高细胞存活率,差异具有统计学意义(P<0.05);锰暴露可上调神经元GAD65蛋白表达水平,差异具有统计学意义(P<0.05),但锰暴露未改变神经元细胞Nav1.1蛋白的表达水平,差异无统计学意义(P>0.05)。结论锰暴露所致神经元损伤及GABA能损伤可能与其Nav1.1蛋白表达无关。

Objective To explore the role of Na^(+)channels on gamma-aminobutyric acid(GABA)in manganese(Mn)-induced neurocytotoxicity.Methods SH-SY5Y cells were used to establish Mn exposure models,which were divided into four groups:blank control group,0.25 mmol/L MnCl_(2),0.50 mmol/L MnCl_(2),and 1.00 mmol/L Mn-Cl_(2).Tetrodotoxin(TTX)0.10μmol/L,0.20μmol/L was used for intervention.MTT was used to measure the cell survival rate,microscope was used for morphological observation,and western blot was used to detect the expression levels of Nav1.1 channel protein and GABA-marked glutamic acid decarboxylase 65(GAD65)protein in Na^(+)channels.Results MnCl_(2)can inhibit cell proliferation,and 0.25 mmol/L MnCl_(2),0.5 mmol/L MnCl_(2),and 1 mmol/L Mn-Cl_(2)can significantly reduce cell survival rate(P<0.05).TTX can improve the neuronal damage caused by manganese exposure and increase cell survival rate(P<0.05).Manganese exposure could up-regulate the expression of GAD65 protein in neurons(P<0.05),but it did not change the expression of Nav1.1 protein in neurons(P>0.05).Conclusion The neuronal damage and GABAergic damage caused by manganese may not be related to the expression of Nav1.1 protein.