硫辛酸对MPTP诱导的小鼠帕金森病模型的神经保护作用

目的:探讨α-硫辛酸(alpha-lipoic acid,ALA)在1-甲基-4-苯基-1,2,3,6-四氢吡啶(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,MPTP)诱导的小鼠帕金森病(Parkinson disease,PD)模型中的神经保护作用。方法:建立MPTP诱导的PD小鼠模型后,通过旷场实验、悬绳实验和转棒实验评估ALA对PD小鼠运动缺陷的影响;通过免疫组化检测ALA对PD小鼠黑质和纹状体多巴胺能神经元的影响;通过高效液相色谱检测ALA对PD小鼠纹状体多巴胺(dopamine,DA)及其代谢产物3,4-二羟基苯乙酸(3,4-dihydroxyphenylacetic acid,DOPAC)释放的影响;通过免疫荧光检测ALA对PD小鼠黑质中小胶质细胞活化以及小胶质细胞中诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)表达的影响;通过Western blot检测ALA对PD小鼠纹状体中酪氨酸羟化酶(tyrosine hydroxylase,TH)和促炎分子白细胞介素1β(interleukin-1β,IL-1β)、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)和环氧合酶2(cyclooxygenase-2,COX-2)表达的影响。结果:行为学实验结果显示,ALA治疗显著增加PD小鼠总移动距离、平均运动速度和悬线实验评分(P<0.05),显著降低转棒实验的下落潜伏期(P<0.01)。免疫组化结果显示,ALA治疗显著增加黑质和纹状体中TH的表达水平(P<0.01)。高效液相色谱结果显示,ALA治疗显著增加纹状体DA和DOPAC的释放水平(P<0.01)。免疫荧光结果显示,ALA治疗显著降低黑质中小胶质细胞的活化和小胶质细胞的iNOS阳性细胞数(P<0.01)。Western blot结果显示,ALA治疗显著增加纹状体中TH的表达,显著降低IL-1β、TNF-α和COX-2表达(P<0.01)。结论:ALA在MPTP诱导的PD小鼠中发挥神经保护作用,能降低小胶质细胞活化,减轻多巴胺能神经元损伤、神经炎症和运动缺陷。

Effects of alpha-lipoic acid on MPTP-induced Parkinson disease in mice

AIM:To investigate the neuroprotective effect of alpha-lipoic acid(ALA)in mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced Parkinson disease(PD).METHODS:After establishment of the MPTP-induced PD mouse model,the effects of ALA on the motor deficits in PD mice were evaluated by open-field test,hanging wire test and rotarod test.The effects of ALA on dopaminergic neurons in substantia nigra and striatum of the PD mice were detected by immunohistochemical staining.The effects of ALA on the release of dopamine(DA)and its metabolite 3,4-dihydroxyphenylacetic acid(DOPAC)in striatum of PD mice were measured by high-performance liquid chromatography.The effects of ALA on activation of microglia in PD mice and the expression of inducible nitric oxide synthase(iNOS)in microglia were examined by immunofluorescence staining.The effects of ALA on the expression of tyrosine hydroxylase(TH),interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α)and cyclooxygenase-2(COX-2)in striatum of PD mice were determined by Western blot.RESULTS:ALA treatment significantly increased the total moving distance,average velocity and hanging wire test score(P<0.05),but significantly decreased the falling lantency of rotarod test(P<0.01)ALA treatment significantly increased the expression levels of TH in substantia nigra and striatum(P<0.01),and the release levels of DA and DOPAC in striatum(P<0.01).ALA treatment significantly decreased microglia activation and iNOS positive microglia in substantia nigra(P<0.01).ALA treatment significantly increased the expression level of TH,significantly decreased the expression levels of IL-1β,TNF-αand COX-2 in the striatum(P<0.01).CONCLUSION:ALA plays a neuroprotective role in the mice with MPTP-induced PD.ALA reduces microglial cell activation,dopaminergic neuron damage and neuroinflammation,and attenuates motor deficits in MPTP-induced PD mice.