p38MAPK通路参与亚急性帕金森病模型小鼠黑质iNOS表达的调控

p38MAPK signaling pathway regulates iNOS expression in nigral cells of the subacute mouse model of Parkinson’s disease

目的:研究1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)所致Parkinson病(PD)小鼠模型黑质p38丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)通路对诱导型一氧化氮合酶(inducible nitric oxide,iN-OS)、半胱氨酸蛋白酶-3(caspase-3)的表达调控,以探讨PD多巴胺能神经元丢失的可能机制。方法:采用MPTP制备PD小鼠模型,观察行为学变化;采用免疫组化和免疫蛋白印迹法,观察黑质区酪氨酸羟化酶(tyrosine hydroxylase,TH)、iNOS、caspase-3和磷酸化p38MAPK(p-p38MAPK)阳性细胞数和蛋白表达水平变化及给予p38MAPK特异性抑制剂SB203580后对上述变化的影响。结果:模型II组TH阳性神经元明显丢失,小鼠出现典型的PD样行为学表现;模型I组小鼠黑质区p-p38MAPK、iNOS、caspase-3阳性细胞数及蛋白水平显著增加。经SB203580处理后,上述变化明显减轻(P<0.01)。结论:p38MAPK通路对PD模型小鼠黑质区细胞凋亡可能起重要的调控作用,抑制该通路具有一定神经保护作用。

Objective： To investigate the effects of p38 mitogen-activated protein kinase （p38MAPK） signaling pathway on the expression of inducible nitric oxide synthase （iNOS） and caspase-3 in substantia nigra （SN） of the mouse model of Parkinson＇s disease （ PD ） induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine （MPTP） and further explore the possible mechanism of the dopaminergic （DA） neuronal loss in SN. Methods：C57BL/6N mice were administrated with MPTP to produce subacute PD model and detected the behavior change. The numbers of TH, iNOS, caspase-3 and p- p38MAPK positive cells, and their expressional level in SN were observed by immunohistochemistry and Western Blot. The above changes, after giving SB203580, the specific p38MAPK inhibitor, were also studied. Results： In the model group-II, TH-positive neurons lost markedly and the mice exhibited the typical PD-like behaviors. In the model group-I, the number of p-p38MAPK, iNOS, caspase-3 immunoreactive cells and their expression level in SN increased markedly. After giving SB203580, the above changes reduced obviously （P 〈 0. 01 ）. Conclusion： p38MAPK pathway may play an important role in mediating neuronal apoptosis in SN in the mouse model of PD, inhibition of the pathway has the neuro- protective effect.