槲皮素通过PI3K/Akt/mTOR通路促进缺血性脑卒中小鼠康复的机制

Quercetin promotes rehabilitation of mice with ischemic stroke via PI3K/Akt/mTOR pathway

目的探讨槲皮素通过磷脂酰肌醇-3(PI3K)/蛋白激酶B(Akt)/哺乳动物雷帕霉素靶蛋白(mTOR)通路促进缺血性脑卒中小鼠康复的机制。方法使用线栓法使大脑中动脉阻塞(MCAO)、构建缺血性脑卒中C57BL/6小鼠模型(40只),纳入10只健康小鼠作为对照组(每日灌胃等体积生理盐水);将40只模型小鼠随机均分为槲皮素组(每日灌胃200 mg/kg槲皮素)、通路抑制组(每日灌胃60 mg/kg NVP-BEZ235)、联合组(每日灌胃200 mg/kg槲皮素和60 mg/kg NVP-BEZ235)及模型组(每日灌胃等体积生理盐水),均给药7 d;采用Moriss水迷宫检测各组小鼠学习记忆能力,并进行脑功能缺陷评分及测算脑梗死灶体积,取海马组织检测炎性因子白细胞介素-6(IL-6)及肿瘤坏死因子-α(TNF-α)、检测氧化应激因子水平、PI3K、AKT、mTOR蛋白表达、磷酸化p-PI3K、p-Akt、p-mTOR水平。结果与对照组相比,其余各组小鼠的穿越原平台次数、目标象限停留时间百分比、超氧化物歧化酶(SOD)水平、PI3K、AKT、mTOR蛋白表达、p-PI3K、p-AKT、p-mTOR水平均减少,逃逸潜伏期、脑功能缺陷评分、脑梗死灶体积、IL-6、TNF-α、MDA水平均升高;与模型组相比,通路抑制组小鼠的穿越原平台次数、目标象限停留时间百分比、SOD水平、PI3K、AKT、mTOR蛋白表达、p-PI3K、p-AKT、p-mTOR水平均减少,逃逸潜伏期、脑功能缺陷评分和脑梗死灶体积、IL-6、TNF-α、MDA水平均升高,槲皮素组则相反,差异有统计学意义(P<0.05)。联合组小鼠与模型组比较上述各指标差异多无统计学意义(P>0.05)。结论槲皮素可促进缺血性卒中小鼠康复,其机制可能与槲皮素调节脑缺血再灌注小鼠PI3K/Akt/mTOR通路功能、影响海马组织中炎症因子及应激反应水平有关。

Objective To investigate the mechanism by which quercetin promotes the rehabilitation of mice with ischemic stroke via phosphatidylinositol-3 kinase(PI3K)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR)pathway.Methods Suture-occluded method was used to induce mouse middle cerebral artery occlusion(MCAO)for establishing ischemic stroke model in 40 C57BL/6 mice,and 10 healthy mice were selected as control group which was daily gavaged with equal volume of normal saline.Forty 40 model mice were randomly divided into quercetin group(daily administration of 200 mg/kg quercetin),pathway inhibition group(daily administration of 60 mg/kg NVP-BEZ235),combination group(daily administration of 200 mg/kg quercetin+60 mg/kg NVP-BEZ235)and model group(daily administration of equal volume normal saline).The treatment lasted for 7 days.Moris water maze was used to test the learning and memory ability of mice in each group,score brain function deficit and calculate cerebral infarction volume.The inflammatory factors interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α)were detected in hippocampus tissues.The levels of oxidative stress factor,the protein expression of PI3K,AKT,mTOR,phosphorylated p-PI3K,p-Akt,p-mTOR were detected.Results When compared to control group,the times of crossing the original platform,the percentage of target quadrant residence time,superoxide dismutase(SOD)level,the expression levels of PI3K,AKT,mTOR,p-PI3K,p-AKT,p-mTOR in other groups were reduced,while escape latency,brain function deficit score,cerebral infarction volume,the levels of IL-6,TNF-α,and MDA were increased.When compared to model group,times of crossing the original platform,the percentage of target quadrant residence time,SOD level,the expression levels of PI3K,AKT,mTOR,p-PI3K,p-AKT,p-mTOR in pathway inhibition group were reduced,while escape latency,brain function deficit score,cerebral infarct volume,the levels of IL-6,TNF-α,and MDA were increased.Quercetin group was opposite to pathway inhibition group(P<0.05).There were no significant differences in the above indexes between combination and model groups(P>0.05).Conclusion Quercetin can promote the rehabilitation of mice with ischemic stroke,and its mechanism may be related to quercetin-mediated regulation of PI3K/Akt/mTOR pathway,inflammatory factors,and stress response in hippocampus of mice with cerebral ischemia reperfusion.