肌肽对血管性认知功能障碍大鼠海马内Akt/mTOR通路及自噬的影响  

Effects of carnosine on hippocampal Akt/mTOR pathway andautophagy in rats with vascular cognitive impairment

作　　者：王高 卢金莹 冉睿黎 赵欣敏 边疆 王宇彤 姜晓涵 杨菁 WANG Gao;LU Jinying;RAN Ruili;ZHAO Xinmin;BIAN Jiang;WANG Yutong;JIANG Xiaohan;YANG Jing(Department of Biochemistry and Molecular Biology,Basic Medical College,Jinzhou Medical University,Jinzhou 121001,China)

机构地区：[1]锦州医科大学基础医学院生物化学与分子生物学教研室,锦州121001

出　　处：《神经解剖学杂志》2024年第6期713-723,共11页Chinese Journal of Neuroanatomy

基　　金：辽宁省教育厅面上项目(2021LJKZ0823)。

摘　　要：目的:观察肌肽(CAR)对血管性认知功能障碍(VCI)大鼠的空间学习记忆能力的影响,并探究Akt/mTOR通路及自噬在其中的作用。方法:将50只雄性SD大鼠随机分为假手术(Sham)组、VCI组及VCI+CAR-L组、VCI+CAR-M组和VCI+CAR-H组。Morris水迷宫实验评测大鼠的空间学习记忆能力;Nissl染色检测海马CA1区细胞损伤的范围和程度;氮蓝四唑法和硫代巴比妥酸法分别检测海马组织中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量;Western Blot测定p-Akt、p-mTOR、Beclin-1以及LC3B蛋白表达,同时免疫荧光染色检测CA1区LC3B表达变化。将SH-SY5Y细胞分为对照(Control)组、氧糖剥夺/再灌注(OGD/R)组、OGD/R+雷帕霉素(RAPA)组、OGD/R+CAR(1.2 mmol/L)组及OGD/R+CAR+RAPA组。噻唑蓝(MTT)检测神经元存活率:Western Blot检测神经元细胞p-mTOR、Beclin-1及LC3B水平,免疫荧光染色检测自噬程度。结果:CAR可改善VCI大鼠学习记忆能力,降低海马组织细胞损伤,抑制氧化应激(P<0.01),提高p-Akt、p-mTOR、p62蛋白的表达(P<0.01或P<0.05),降低Beclin-1的表达和LC3B II/I的比值(P<0.01或P<0.05)。CAR可提高SH-SY5Y各组细胞OGD/R后的存活率(P<0.01),抑制海马神经元的自噬。此外,RAPA的干预抑制了CAR的治疗效果,降低SH-SY5Y各组的存活率(P<0.01),增强了细胞自噬。结论:CAR可改善大鼠VCI损伤,其机制可能通过抑制氧化应激、激活神经细胞中的Akt/mTOR信号通路,进而抑制过度自噬发挥保护作用。Objective:To investigate the effects of carnosine(CAR)on the spatial learning and memory abilities of rats with vascular cognitive impairment(VCI),and to explore the roles of the Akt/mTOR pathway and autophagy in this process.Methods:Fifty male Sprague-Dawley(SD)rats were randomly divided into sham-operated(Sham)group,VCI group,VCI+CAR-L group,VCI+CAR-M group,and VCI+CAR-H group.The spatial learning and memory abilities of rats were evaluated by the Morris water maze experiment;Nissl staining was used to detect the damage in the hippocampal CA1 region;the nitroblue tetrazolium and thiobarbituric acid methods were used to measure the activities of superoxide dismutase(SOD)and malondialdehyde(MDA)content in hippocampal tissue;Western Blot was performed to determine the expression of p-Akt,p-mTOR,Beclin-1,and LC3B proteins,and immunofluorescent staining was conducted to detect changes in LC3B expression in the CA1 region.SH-SY5Y cells were divided into control group,oxygen-glucose deprivation/reperfusion(OGD/R)group,OGD/R+rapamycin(RAPA),OGD/R+CAR(1.2 mmol/L)group,and OGD/R+CAR+RAPA group.Methyl thiazolyl tetrazolium assay was used to detect neuronal survival rate;Western Blot was used to detect the levels of p-mTOR,Beclin-1,and LC3B in neuronal cells;immunofluorescent staining was performed to assess the degree of autophagy.Results:CAR could improve the learning and memory abilities of VCI rats,reduce hippocampal tissue cell damage,and inhibit oxidative stress(P<0.01).CAR increased the expression of p-Akt,p-mTOR,and p62 proteins(P<0.01 or P<0.05)and decreased the expression of Beclin-1 and the ratio of LC3B II/I(P<0.01 or P<0.05).CAR significantly increased the survival rate of SH-SY5Y cells after OGD/R(P<0.01)and inhibited autophagy in hippocampal neurons.Furthermore,the intervention with RAPA counteracted the therapeutic effect of CAR,reduced the survival rate of SH-SY5Y groups(P<0.01),and enhanced autophagy.Conclusion:CAR can improve rat VCI injury,and its mechanism may involve inhibiting oxidative stress,activa

关 键 词：肌肽 血管性认知障碍 自噬 Akt/mTOR信号通路 氧化应激 大鼠 

分 类 号：R749.1[医药卫生—神经病学与精神病学]