锰暴露不同时长对神经元细胞突触囊泡及其相关蛋白的影响

目的 研究锰暴露不同时长对神经元细胞突触囊泡及其相关蛋白的影响。 方法 将体外培养的神经元,分别用100 μM 锰处理0、6、12、18、24 h后,观察细胞活力及培养液中LDH的释放量,测定SNARE复合物相关蛋白的基因及蛋白表达,以及活动性突触囊泡的释放。 结果 神经元细胞用100 μM锰暴露不同时长后,神经元损伤逐渐加重(P<0.01);与对照组比较,Syntaxin 1A的基因及蛋白表达均未见明显改变(P>0.05),SNAP 25的基因和蛋白表达均逐渐下降(P<0.05),VAMP 2的基因和蛋白表达均逐渐升高(P<0.01),进而导致SNARE复合物蛋白形成先升高后下降的趋势,同时活动性突触囊泡的释放也出现相应改变。 结论 锰暴露可以时间依赖性的干扰SNARE复合物相关蛋白表达,减少了神经元细胞内SNARE复合物的形成,进而导致活动性突触囊泡减少,造成神经递质释放紊乱。

Effects of manganese exposure for differen time on synaptic vesicle and its associated proteins in neurons

Objective The aim of this study is to explore the effects of manganese (Mn) exposure for different time on synaptic vesicle and its associated proteins in neurons. Methods After the primary cultured neurons in vitro were treated with Mn (100μM) for 0,6,12,18 or 24 hours, the cell viability and LDH release in culture medium were detected. The expression of soluble NSF accessory protein receptor(SNARE) complex gene and protein and the number of active synaptic vesicles were determined. Results With the increase of Mn exposure time, neuronal cell damage gradually aggravated(P<0.01). Compared with the control group, syntaxin 1A gene and protein expression in the Mn exposed cells showed no significant changes (P>0.05). Synaptosome-associated protein of 25 kDa (SNAP 25) gene and protein expressions were gradually decreased with exposure time (P<0.05), while vesicle-associated membrane protein 2(VAMP 2)gene and protein expressions were gradually increased (P<0.01), which led to first increase and then decrease of the formation of SNARE complex. At the same time, the release of active synaptic vesicles changed accordingly. Conclusions Mn disturbs the expressions of SNARE complex relevant proteins and reduces the formation of the SNARE complex in a time-dependent manner, which leads to reduction of activity of synaptic vesicles and to neurotransmitter release disorders.