右美托咪定预处理激活PI3K/mTOR/ULK1通路发挥抗氧化应激和保护大鼠脑缺血/再灌注损伤的分子机制研究  

Molecular mechanism of dexmedetomidine preconditioning to activate PI3K/mTOR/ULK1 pathway to protect against oxidative stress and cerebral ischemia/reperfusion injury in rats

作　　者：尹顺花 金辉[2] 肖志博[2] 葛树胜 吴小精 李媛[2] Yin Shunhua;Jin Hui;Xiao Zhibo;Ge Shusheng;Wu Xiaojing;Li Yuan(Department of Anesthesiology,the First Affiliated Hospital of Hainan Medical College,Haikou 570100,China)

机构地区：[1]海南省妇女儿童医学中心 [2]海南医学院第一附属医院麻醉科,海口570100

出　　处：《脑与神经疾病杂志》2022年第11期688-693,共6页Journal of Brain and Nervous Diseases

基　　金：海南省自然科学基金青年基金项目(8200N397)。

摘　　要：目的探索右美托咪定(Dex)预处理在缓解大鼠脑缺血/再灌注(CI/R)损伤中的作用及其分子机制。方法选取48只6~8w龄雄性SD大鼠,每组12只,随机分为假手术(Sham)组,大脑中动脉闭塞(MCAO)模型组,Dex预处理(MCAO+Dex)组和ULK1抑制剂(SBI-0206965)联合Dex预处理(MCAO+Dex+SBI-0206965)组。TTC染色检测脑梗死体积并计算脑水肿指数;ELISA测定大鼠脑组织活性氧自由基(ROS)和超氧化物歧化酶(SOD)活性及丙二醛(MDA)水平;Western blot检测大鼠脑组织自噬标志物LC3-Ⅰ、LC3-Ⅱ、Beclin、p62的表达及PI3K/mTOR/ULK1通路p-PI3K、p-mTOR及p-ULK1的水平。结果与假手术(Sham)组相比,MCAO组大鼠脑梗死体积百分比、脑水肿指数、ROS和MDA水平、LC3-Ⅱ/LC3-Ⅰ的比值、Beclin的表达显著升高(P<0.01),SOD水平、p62、p-PI3K、p-mTOR及p-ULK1的水平显著下调(P<0.01)。与MCAO组相比,Dex组显著逆转了上述情况(P<0.01)。而SBI-0206965抵消了Dex预处理的保护作用,与Dex组相比,MCAO+Dex+SBI-0206965组大鼠脑梗死体积百分比和脑水肿指数显著升高(P<0.01),氧化应激水平及自噬标志物的表达显著上调(P<0.01),并下调SOD水平及抑制PI3K/mTOR/ULK1通路的活化(P<0.01)。结论Dex预处理是通过激活PI3K/mTOR/ULK1通路发挥抗氧化应激和保护大鼠脑缺血/再灌注损伤的,抑制ULK1的磷酸化,将抵消Dex的保护作用。Objective Explore the protective role and its molecular mechanisms of dexmedetomidine(Dex)preconditioning on cerebral ischemia/reperfusion(CI/R)injury.Methods 48 male SD rats aged 6-8 weeks were randomly divided into sham operation(Sham)group,middle cerebral artery occlusion(MCAO)model group,Dex preconditioning(MCAO+Dex)group and ULK1 inhibitor(SBI-0206965)combined with Dex preconditionning(MCAO+Dex+SBI-0206965)group.12 rats in each group.TTC staining was used to detect cerebral infarct volume and calculate cerebral edema index.ELISA was used to measure the oxidative stress ROS activity,SOD activity and MDA levels;Western blot was used to detect the expression of autophagy markers LC3-I,LC3-II,Beclin,p62 and p-PI3 K,p-mTOR and p-ULK1 levels in rat brain tissues.Results Compared with Sham group,the percentage of cerebral infarct volume,cerebral edema index,ROS and MDA levels,LC3-Ⅱ/LC3-Ⅰ ratio,and the expression of Beclin in the MCAO group were significantly increased(P<0.01),with the levels of SOD,p62,p-PI3 K,p-mTOR and p-ULK1 significantly decreased(P<0.01).Compared with the MCAO group,the Dex preconditioning group was significantly reversed the above situation(P<0.01).SBI-0206965 abolished the protective effect of Dex preconditioning.Compared with Dex group,the percentage of cerebral infarct volume and cerebral edema index of rats in the MCAO+Dex+SBI-0206965 group were significantly increased(P<0.01),and the levels of ROS and MDA and autophagy markers were significantly increased(P<0.01),with the levels of SOD decreased and the activation status of PI3 K/mTOR/ULK1 pathway inhibited(P<0.01).Conclusion Dex preconditioning plays an anti-inflammatory effect and protective roles on rats with cerebral ischemia/reperfusion injury by activating the PI3 K/mTOR/ULK1 pathway.Inhibition of the phosphorylation of ULK1 will abolish the protective roles of Dex.

关 键 词：右美托咪定 脑缺血/再灌注损伤 自噬 PI3K/mTOR/ULK1通路 

分 类 号：R743.34[医药卫生—神经病学与精神病学]