没食子酸对MPTP所致帕金森病多巴胺能神经元损伤的保护作用

Protective Effects of Gallic Acid on the MPTP-Mediated Dopaminergic Neurons Damage in Parkinson's Disease

目的研究没食子酸对帕金森病(PD)动物模型的神经保护作用及相关机制。方法36只小鼠随机分为对照组、1-甲基-4-苯基,1,2,3,6-四氢吡啶(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,MPTP)组和没食子酸组,MPTP组和没食子酸组小鼠每天给予30 mg·kg^-1 MPTP腹腔注射,连续注射7 d,对照组小鼠同时给予等量生理盐水,没食子酸组小鼠从第1天开始每天给予200 mg·kg^-1没食子酸连续灌胃14 d,MPTP组和对照组小鼠均给予等量生理盐水。给药结束后7 d用爬杆实验和悬挂实验分析行为学功能,采用免疫组化检测黑质纹状体酪氨酸羟化酶(TH)表达情况,TUNEL法检测黑质神经细胞凋亡,qRT-PCR分析SIRT3 mRNA水平,Western blot检测蛋白表达情况。结果与对照组比较,MPTP组小鼠运动协调能力减弱,黑质和纹状体TH表达减少,黑质神经细胞凋亡明显增多,黑质SIRT3 mRNA和蛋白表达水平明显降低、超氧化物歧化酶2(SOD2)蛋白表达减少,组间比较差异均具有统计学意义(P<0.05)。没食子酸组小鼠经药物干预后,运动协调能力增强,黑质和纹状体TH表达增多、黑质神经细胞凋亡受到抑制,SIRT3 mRNA和蛋白表达水平升高,SOD2蛋白表达上调,与模型组比较,差异均具有统计学意义(P<0.05)。结论没食子酸可改善PD模型小鼠行为学功能障碍,抑制多巴胺能神经元损伤,作用机制可能与其上调SIRT3基因表达有关。

OBJECTIVE To study the neuroprotective effects of gallic acid in animal models of Parkinson's disease(PD)and its related molecular mechanisms.METHODS Thirty-six mice were randomly divided into control group,1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)group and gallic acid group.Mice in MPTP group and gallic acid group were given an intraperitoneal injection of 30 mg·kg^-1 MPTP daily for 7 d.The mice in control group were given the same amount of normal saline at the same time.The mice in gallic acid group received oral administration of 200 mg·kg^-1 gallic acid daily from the first day,gallic acid was administered continuously for 14 d,and mice in MPTP group and control group received the same amount of normal saline.After 7 d of drug administration,the behavioral function was evaluated by rod climbing test and suspension test.The expression of tyrosine hydroxylase(TH)in the substantia nigra and striatum were detected by immunohistochemistry.The number of apoptotic neurons in the substantia nigra were measured by TUNEL assay.SIRT3 mRNA levels were analyzed by qRT-PCR,and protein expression levels were detected by Western blot.RESULTS Compared with the control group,the ability of motor coordination weakened,the TH expression levels decreased in the substantia nigra and striatum,the number of apoptotic neurons in the substantia nigra significantly increased,the SIRT3 mRNA and protein levels in the substantia nigra obviously declined,and the SOD2 protein expression also dramatically reduced in the MPTP group,the differences between the groups were all statistically significant(P<0.05).After treatment with gallic acid,the ability of motor coordination enhanced,the TH expression level elevated,the number of apoptotic neurons markedly reduced,SIRT3 mRNA and protein levels increased,and SOD2 protein expression also up-regulated in the gallic acid group.Compared with the MPTP group,the differences were all statistically significant(P<0.05).CONCLUSION Gallic acid can improve the behavioral dysfunction and inhibit dopaminergic neurons damage in PD mice.The mechanism of action may be related to the up-regulation of SIRT3 gene expression.