SIRT3介导褪黑激素保护帕金森病多巴胺能神经元的作用机制

目的研究SIRT3在褪黑激素保护帕金森病(Parkinson’s disease,PD)多巴胺能神经元中的作用。方法48只小鼠随机分为对照组、模型组和治疗组,治疗组小鼠给予褪黑激素(10 mg·kg-1)和MPTP(30 mg·kg-1)腹腔注射,模型组小鼠给予MPTP腹腔注射,对照组小鼠同时给予等量生理盐水,褪黑激素连续给药14 d。采用免疫组化分析黑质TH、Iba-1表达情况,ELISA法检测中脑组织氧化应激指标(ROS、MDA、SOD)及炎症因子(TNF-α、IL-1β)水平,实时定量PCR分析SIRT3 mRNA水平,免疫荧光和Western blot检测蛋白表达情况。结果与对照组比较,模型组小鼠黑质TH表达减少、Iba-1表达增多,中脑组织氧化应激与炎症损伤明显增强,黑质SIRT3 mRNA和蛋白表达水平明显降低,SOD2蛋白表达减少,iNOS蛋白表达增多,组间比较差异均具有统计学意义( P <0.05)。治疗组小鼠经褪黑激素干预后,TH表达增多、Iba-1表达减少,氧化应激与炎症损伤明显减弱,SIRT3 mRNA和蛋白表达水平升高,SOD2蛋白表达上调,iNOS蛋白表达下调,与模型组比较,差异均具有统计学意义( P <0.05)。 结论 褪黑激素通过上调SIRT3表达抵抗PD多巴胺能神经元损伤,作用机制与其抑制小胶质细胞激活减轻氧化应激和炎症损伤有关。

Role of SIRT3 in molecular mechanism of melatonin protecting dopaminergic neurons in Parkinson's disease

Aim To investigate the role of SIRT3 in the molecular mechanism of melatonin protecting dopaminergic neurons in Parkinson’s disease(PD).Methods Forty-eight mice were randomly divided into control group,model group and treatment group.The mice in treatment group received intraperitoneal injection of melatonin(10 mg·kg-1)and MPTP(30 mg·kg-1).The mice in model group only received intraperitoneal injection of MPTP(30 mg·kg-1),and the mice in control group received the same amount of normal saline.Melatonin was administered continuously for 14 days.The expressions of TH and Iba-1 in substantia nigra were analyzed by immunohistochemistry.The levels of oxidative stress(ROS,MDA,SOD)and inflammatory factors(TNF-α,IL-1β)in the midbrain were measured by ELISA.SIRT3 mRNA level was analyzed by qRT-PCR,and protein expression level was detected by immunocytochemistry assay and Western blot.Results Compared to control group,the TH expression decreased and Iba-1 expression increased in the substantia nigra,the oxidative stress and inflammatory injury in the midbrain were significantly enhanced,the SIRT3 mRNA and protein levels in the substantia nigra obviously declined,the SOD 2 protein expression was also dramatically reduced,and the iNOS protein expression was elevated in model group;the differences between the groups were all statistically significant(P<0.05).After treatment with melatonin,the TH expression increased,Iba-1 expression decreased,oxidative stress and inflammatory injury markedly decreased,SIRT3 mRNA and protein levels were elevated,SOD 2 protein expression was up-regulated,and iNOS protein expression was down-regulated in treatment group.Compared to model group,the differences were all statistically significant(P<0.05).Conclusions Melatonin can counteract the damage of dopaminergic neurons by up-regulating the expression of SIRT3 in PD animal model.Its mechanisms of action are related to inhibiting microglia activation,and alleviating oxidative stress and inflammation injury.