急性和慢性低O_2高CO_2大鼠海马线粒体生物合成改变及其与认知障碍的关系  

Effects of acute and chronic hypoxia-hypercapnia on mitochondrial biogenesis in rat hippocampus and its relationship with cognitive impairment

作　　者：闵晶晶 顾群[1] 陈琪[2] 王小同[3] MIN Jingjing;GU Qun;CHEN Qi;WANG Xiaotong(Department of Neurology,Huzhou First People’s Hospital,Huzhou,313000;Department of Nephrology,Huzhou First People’s Hospital,Huzhou,313000;Department of Rehabilitation,the Second Affiliated Hospital of Wenzhou Medical University,Wenzhou,325027)

机构地区：[1]湖州市第一人民医院神经内科,浙江湖州313000 [2]湖州市第一人民医院肾内科,浙江湖州313000 [3]温州医科大学附属第二医院康复科,浙江温州325027

出　　处：《温州医科大学学报》2018年第12期871-875,880,共6页Journal of Wenzhou Medical University

基　　金：浙江省自然科学基金资助项目(Y205233);浙江省科技厅项目(2017C37106);浙江省医药卫生科技项目(2015DTA017);湖州市科技局公益性应用研究项目(2016GYB25)

摘　　要：目的:探讨急慢性低O_2高CO_2对大鼠认知功能的影响及其改变是否与海马线粒体生物合成有关。方法:将48只雄性SD大鼠用随机数字表法分为对照组、急性组和慢性组,每组16只;Morris水迷宫检测大鼠认知功能;透射电镜观察海马区线粒体形态;Western blot法检测线粒体生物合成蛋白PGC-1、NRF-1、TFAM表达;实时定量PCR法检测线粒体DNA(mtDNA)的拷贝数量。结果:与对照组比,急性组大鼠逃避潜伏期和游泳距离差异无统计学意义(P>0.05)。慢性组大鼠逃避潜伏期和游泳距离明显长于对照组(P<0.05)。在空间平台探索实验中,与对照组比,急性组穿越平台次数差异无统计学意义(P>0.05),而慢性组穿越平台次数较对照组明显减少(P<0.05)。透射电镜观察显示,与对照组比,急性组大鼠海马区线粒体双层膜完整,结构尚清晰,而慢性组大鼠海马区线粒体膜出现肿胀,膜模糊不清,部分膜破裂,线粒体空泡变,嵴紊乱或疏松溶解,部分消失。Western blot结果显示,与对照组比,急性组大鼠海马PGC-1蛋白水平明显增加(P<0.01),其下游级联蛋白NRF-1、TFAM蛋白表达均较对照组表达增加(P<0.05);慢性组PGC-1α、NRF-1、TFAM表达较对照组减少(P<0.01)。RT-PCR结果显示,急性组mtDNA拷贝数较对照组增加(P<0.01),慢性组mtDNA较对照组减少(P<0.05)。结论:线粒体生物合成水平的下降可能是长期低O_2高CO_2暴露下大鼠学习记忆障碍的原因之一。Objective:To investigate the relationship between changes of mitochondrial biogenesis and learning and memory impairment in rats after acute or chronic exposure to hypoxia-hypercapnia.Methods:Forty eight SD male rats were randomly divided into three groups by the random number tables method as follows:the normal control group,the acute hypoxia-hypercapnia group,the chronic hypoxia-hypercapnia group.The cognitive ability was assessed by the Morris water maze.The mitochondrial structure was observed by the electronmicroscopy.The protein expression of PGC-1α,NRF-1,TFAM were measured by the western blot.The copy number of mtDNA was detected by Real-Time PCR.Results:After exposure,the acute group performed almost similar to the normal control group in exploring the hidden platform.While the chronic group displayed worse performance during navigation test(P<0.05).In the probe trial on the last day,the acute group showed no difference with the normal control group,the crossing number of the chronic group was decreased(P<0.05).The electron-microscopy showed the mitochondrial structure of the acute group showed no obvious damage.The mitochondrial membrane of the chronic group was edema and obscure,partially destroyed,and the cristae was loosen and disorganized,partially disappeared.Western blot showed the protein expression of PGC-1α(P<0.01),NRF-1(P<0.05),TFAM(P<0.05)were significantly increased in the acute group,but all markedly decreased in the chronic group.Real time PCR showed acute exposure induced an increase of the mtDNA copy number(P<0.01),while the expression in the chronic group significantly down-regulated(P<0.05).Conclusion:The downregulation of mitochondrial biogenesis may contribute to the cognitive function defects of long-term hypoxia-hypercapnia exposure rats.

关 键 词：缺氧 高碳酸血症 线粒体 认知 线粒体DNA 大鼠 

分 类 号：R563[医药卫生—呼吸系统]