血管活性肠肽对MPTP亚急性帕金森病模型小鼠突触的影响

Effects of vasoactive intestinal peptide on synapse of MPTP-induced mice with Parkinson's disease

目的探讨血管活性肠肽(VIP)对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)诱导的帕金森病(PD)小鼠模型突触及其行为学的影响。方法雄性C57BL/6 J小鼠30只,随机分为生理盐水(NS)组、MPTP组、MPTP+VIP组。利用Tru Scan系统测定小鼠的行为学变化;免疫组织化学染色法检测黑质和纹状体区酪氨酸羟化酶(TH)的表达及纹状体区突触小泡膜蛋白2(VAMP2)和突触素1(SYN1)的表达变化;运用免疫印迹法检测VAMP2和SYN1的表达变化;并通过透射电子显微镜观察黑质区突触的结构改变。结果行为学结果统计学分析,MPTP组小鼠的垂直运动距离比对照组明显减少,而给予VIP的小鼠明显高于MPTP组小鼠。MPTP组TH、VAMP2和SYN1表达均明显少于NS组,而MPTP+VIP组显著高于MPTP组。透射电子显微镜结果显示,NS组神经突触结构完整;模型组神经突触数量少,突触间隙不清,突触前成分的线粒体出现髓样变,并且突触小泡数量减少;MPTP+VIP组神经突触结构基本正常。结论 VIP可使MPTP模型小鼠VAMP2和SYN1的表达上调,减少突触结构的损伤,保护黑质纹状体系统TH的表达,从而改善其运动状态。

Objective To study the effects of vasoactive intestinal peptide（ VIP） on synaptic and behavioral alterations in the mice model of Parkinson’s disease（ PD） induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine（ MPTP）. Methods Thirty male C57 BL/6 J mice were randomly divided into normal saline（ NS） group,MPTP group and MPTP ＋ VIP group. The behavioral changes of mice were measured by the Tru Scan system. The expression of tyrosine hydroxylase（ TH） in the substantia nigra（ SN） and striatum and vesicle-associated membrane protein 2（ VAMP2）and synapsin 1（ SYN1） in the striatum were examined by immunohistochemistry,and the levels of VAMP2 and SYN1 were analyzed by Western blotting. The synaptic structural changes in the SN were observed by transmission electron microscopy. Results In the behavioral test,the MPTP group had a significantly lower vertical movement distance than that of the control group,while the MPTP group was markedly higher than that of MPTP group. Compared with the MPTP group,VIP treatment obviously increased the average absorbance（ AA） of TH,VAMP2 and SYN1 immunolabeling in striatum and the number of dopaminergic neurons in the SN,while the levels of the VAMP2 and SYN1 proteins also elevated. Synapse density in the model group was less than that in the control group. The amount of synaptic vesicles was decreased in the model group compared to the control,but normalized in the MPTP ＋ VIP group. Conclusion VIPadministration can up-regulate the expression of VAMP2 and SYN1,mitigate synaptic damage,protect dopaminergic neurons and improve movement in the MPTP model mice.