EGCG对氧糖剥夺/再灌注神经元氧化应激及Nrf2/HO-1通路的影响

Effect of EGCG on oxidative stress and Nrf2/HO-1 pathway in neurons exposed to oxygen-glucose deprivation/reperfusion

目的:研究表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)对氧糖剥夺/再灌注(oxygen-glucose deprivation/reperfusion,OGD/R)导致的神经元氧化应激损伤及核因子E2-相关因子2(nuclear factor erythroid 2-related factor2,Nrf2)/血红素加氧酶-1(heme oxygenase-1,HO-1)通路的影响。方法:取原代培养的大鼠大脑皮层神经元,建立OGD/R损伤细胞模型。于OGD/R前加入不同浓度(12.5,25.0,50.0,100.0μmol/L)EGCG,再灌注后,测定细胞活力、活性氧(ROS)水平、丙二醛(MDA)含量、超氧化物歧化酶(SOD)及谷胱甘肽过氧化物酶(GSH-Px)活性,检测HO-1mRNA,HO-1蛋白及细胞核Nrf2蛋白表达水平。结果:OGD/R导致神经元细胞活力降低,ROS水平和MDA含量升高,SOD和GSH-Px活性降低,HO-1 mRNA,HO-1蛋白及细胞核Nrf2蛋白表达增多(P<0.01)。EGCG能明显促进OGD/R神经元存活,降低ROS水平和MDA含量,提高SOD和GSH-Px活性,上调HO-1 mRNA,HO-1蛋白及细胞核Nrf2蛋白表达水平(P<0.01)。结论:EGCG能减轻OGD/R诱导的神经元氧化应激损伤,可能与激活Nrf2/HO-1信号通路,增强神经元的抗氧化能力有关。

Objective： To explore the eff ect of epigallocatechin gallate （EGCG） on oxidative stress and Nrf2/HO-1 pathway in neurons subjected to oxygen-glucose deprivation/reperfusion （OGD/R）.Methods： Primary cultured cerebral cortical neurons were prepared from Sprague-Dawley rats, and the OGD/R cell model was established. After pretreatment with EGCG at different concentrations （12.5, 25.0, 50.0 or 100.0 μmol/L）, the neurons were subjected to OGD/R. The cell viability,reactive oxygen species （ROS） level and malondialdehyde （MDA） content were assessed after reperfusion. The superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） activities were measured. The expression of Nrf2 protein in nucleus, HO-1 mRNA and protein were detected.Results： OGD/R treatment reduced the cell viability, elevated ROS level and MDA content,decreased SOD and GSH-Px activities. The expression of Nrf2 protein in nucleus, HO-1 mRNA and protein were increased （P〈0.01）. Pretreatment with EGCG promoted the survival of neurons exposed to OGD/R, decreased ROS level and MDA content while increased SOD and GSHPx activities. The levels of Nrf2 protein in nucleus, HO-1 mRNA and protein were pregulated （P〈0.01）. Conclusion： EGCG can reduce the oxidative stress of neurons subjected to OGD/R, which may be related to activation of Nrf2/HO-1 signal pathway and enhancement of the antioxidant ability of neurons.