EGCG对体外应激海马神经元的保护作用及其机制探讨

STUDY ON THE NEUROPROTECTIVE EFFECT OF EGCG ON HIPPOCAMPAL NEURONS UNDER STRESS IN VITRO AND ITS MECHANISM

目的观察表没食子儿茶素没食子酸酯(EGCG)对体外应激海马神经元的保护作用,并探讨其相关作用机制。方法体外培养新生大鼠海马神经元,于原代培养D13时加入不同浓度的皮质酮,采用CCK8(cell counting kit-8)法检测对神经元存活率的影响;加入EGCG(0、0.1、1、5、10μmol/L)预处理24h后,加入皮质酮(CORT,1×10-5mol/L)建立应激损伤模型,采用CCK8法检测神经元的存活率;然后加入LY294002(PI3K/AKT特异性阻断剂)和U012(6ERK1/2特异性阻断剂),检测细胞存活率的改变,并以Hoechst33342核染色法检测细胞凋亡情况。结果皮质酮在10-6～10-4mol/L范围内对海马神经元的神经毒性作用呈现浓度-时间依赖性;0.1μmol/L EGCG处理对皮质酮造成的海马神经元损伤具有保护作用,能够增加细胞存活率,降低细胞凋亡的发生;而加入信号通路阻断剂LY294002(10 mol/L)和U0126(10 mol/L)后,此保护作用受到抑制,其能抑制EGCG对抗CORT引起的神经元细胞存活率下降,细胞凋亡增多。结论 EGCG处理对皮质酮造成的大鼠海马神经元损伤具有保护作用,其作用机制可能与EGCG调控PI3K/AKT、ERK1/2信号转导通路相关。

Objective To examine the protective effect of epigallocatechin gallate （EGCG） on hippocampal neurons under stress in vitro and to explore the possible related mechanisms. Methods Primarily cultured hippocampal neurons from neonatal rats were divided into normal control group, corticosterone （CORT） group, EGCG＋CORT group, EGCG＋CORT＋inhibitor group （CORT, EGCG, PI3KJAKT specific inhibitor, LY294002 or ERK1/2 specific inhibitor, U0126） in different concentrations respectively. The neurons survival rate was measured by colorimetric assay （CCK-8 kit）. Hoeehst33342 nuclear staining was used to observe the morphology of apoptotic neurons. Result 0. l btmol/L EGCG could markedly increase the survival rate of under stress hippocampal neurons treated by CORT （1 X 10-Smol/L） under stress. However, the neuroprotective effect of EGCG could be precluded by 10 gmol/L LY294002 or U0126. Conclusion EGCG has neuroprotective effect against hippocampal neurons treated by corticosterone under stress in vitro and this effect is partially through PI3K/AKT and ERK1/2 pathways.