肢体缺血再灌注大鼠心肌中的氧化应激及HO-1mRNA的表达

发布时间：2018-06-17 05:18

本文选题：肢体缺血再灌注 + 氧化应激　；参考：《中南大学》2008年硕士论文

【摘要】： 背景与目的:肢体缺血再灌注损伤临床上极为常见,外周血管手术、肢体的创伤、断肢再植术、血栓形成、腹主动脉瘤手术、挤压综合征等均可引起肢体缺血再灌注损伤。近年研究发现,肢体缺血再灌注损伤不仅影响局部缺血组织的存活和功能,而且还可造成全身炎症反应综合征,累及心、肝、肺、肾、小肠、脑等远隔器官、导致多器官功能受损,其中以心血管系统的损伤最为重要。目前对肢体缺血后所致的肺,脑,肝,肠损伤机制的研究较多,对骨胳肌缺血再灌注所致心肌损伤病理生理机制,至今尚未完全阐明,大量研究表明:严重的肢体缺血再灌注损伤可导致应激性的高血压,应激性心律失常,应激性心肌缺血,心功能不全等,血红素加氧酶-1(heme oxygenase-1,HO-1)是目前发现的受最多因素诱导的应激蛋白。这些刺激的共同点是能造成氧化应激。HO-1具有抗炎、抗细胞凋亡、抗增殖、抗氧化的性质,还有免疫应答等方面具有重要的作用,并成为近几年的研究热点。本实验应用止血带构建大鼠下肢缺血再灌注模型,观察肢体缺血再灌注后心肌病理学改变,氧化应激机制及诱导型血红素氧化酶(HO-1)的表达来说明心肌的损伤及自身保护机制。本实验分为两个部分:一,观察肢体缺血再灌注后心肌的损伤变化,并了解氧化应激在肢体缺血再灌注后继发的心肌损伤中的作用。二,观察内源性HO-1在肢体缺血再灌注后心肌中的表达变化的规律及其意义。方法:本实验应用止血带捆扎大鼠下肢来构造肢体缺血再灌注模型,将实验的大鼠随机分为七组。即:正常组,缺血4小时再灌注2小时组,再灌注4小时组,再灌注6小时组,再灌注8小时组,再灌注16小时组,再灌注24小时组。第一部分实验:应用光镜观察心肌组织的病理变化;分别测定血清及心肌组织中的丙二醛(MDA)含量、总超氧化物歧化酶(T-SOD)活力及髓过氧化物酶(MPO)活性。第二部分实验:应用反转录—多聚酶链反应(RT-PCR)检测心肌HO-1mRNA表达的变化规律。结果:缺血再灌注4,6小时,心肌细胞明显肿胀,肌间隙增宽,小血管充血明显,肌间隙内可见大量红细胞漏出,肌间隙有核细胞明显增多,再灌注24小时上述改变减轻。与正常组比较,血浆MDA及心肌MDA:缺血再灌注各组均明显升高(P＜0.01),再灌注4h达高峰;血浆SOD:缺血再灌注各组均明显下降(P＜0.01),再灌注4小时达最低值,心肌SOD:再灌注各组均明显下降(P＜0.01),再灌注8小时达最低值;血浆及心肌MPO:缺血再灌注2h～8h出现明显升高(P＜0.01),血浆MPO 4h达高峰,心肌MPO 6h达高峰,16,24h下降。肢体缺血再灌注可诱导HO-1mRNA在心肌表达上调,与正常组比较,再灌注2h,HO-1mRNA表达无显著变化(P＞0.05);再灌注4h,6h,8h,16h,24h后HO-1表达显著增强(P＜0.01),并在16h达高峰。结论:肢体缺血再灌注可造成心肌损伤,再灌注4-6小时心肌损伤最重,全身及心肌局部的炎细胞聚集活化,炎性因子的激活和过度的氧化应激及氧化抗氧化失衡是肢体缺血再灌注致心肌损伤的机制,机体存在自身保护机制,活性氧族及炎性因子能上调HO-1的表达,对抗氧化应激,从而发挥心肌细胞保护作用。
[Abstract]:BACKGROUND & OBJECTIVE : Limb ischemia - reperfusion injury is very common in limb ischemia - reperfusion injury .

To observe the changes of myocardial pathology , oxidative stress and inducible heme oxygenase ( HO - 1 ) after limb ischemia - reperfusion , the effects of oxidative stress on myocardial injury following limb ischemia - reperfusion were observed .

Methods : The experimental rats were randomly divided into seven groups . The rats were randomly divided into seven groups : normal group , 4 - hour ischemia - reperfusion group , reperfusion for 4 - hour group , reperfusion for 6 - hour group , reperfusion for 8 - hour group , reperfusion for 16 - hour group and reperfusion for 24 - hour group . First part : the changes of myocardial HO - 1mRNA expression were detected by reverse transcription - polymerase chain reaction ( RT - PCR ) .

Results : After ischemia / reperfusion for 4 and 6 hours , the myocardial cells were obviously swollen , the width of the muscle was increased , the congestion of small blood vessels was significantly increased , there was a significant increase in myocardial MDA and myocardial MDA in the muscle gap ( P < 0.01 ) . After reperfusion for 4 hours , the expression of HO - 1 mRNA increased significantly ( P < 0.01 ) , and the expression of HO - 1 mRNA increased significantly after reperfusion for 4 hours , 6 h , 8 h , 16 h and 24 h ( P < 0.01 ) , and peaked at 16 h .

Conclusion : Limb ischemia - reperfusion can cause myocardial injury , reperfusion 4 - 6 hours myocardial injury heaviest , systemic and myocardial local inflammatory cell aggregation activation , inflammatory factor activation and excessive oxidative stress and oxidation resistance imbalance are the mechanism of myocardial injury caused by ischemia - reperfusion injury , the organism has its own protective mechanism , active oxygen species and inflammatory factor can regulate the expression of HO - 1 and resist oxidative stress , thus playing the protective effect of myocardial cell .
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：R363

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