BI-1在心肌缺血再灌注损伤中的作用及机制研究  

Role and Mechanism of bi-1 in Myocardial Ischemia-reperfusion Injury

作　　者：钟小兰[1] 班努·库肯[1] 景江新[1] Zhong Xiaolan;Bannu·Kuken;Jing Jiangxin(Department of Cardiology,The Second Affiliated Hospital of Xinjiang Medical University,Xinjiang 830063,China)

机构地区：[1]新疆医科大学第二附属医院心内科,乌鲁木齐830063

出　　处：《医学研究杂志》2020年第9期87-93,共7页Journal of Medical Research

基　　金：新疆维吾尔自治区自然科学基金资助项目(2019D01C241)。

摘　　要：目的探讨凋亡抑制基因BI-1(Bax inhibitor-1,BI-1)在心肌缺血再灌注损伤中的作用及机制研究。方法构建大鼠心肌缺血再灌注损伤和H9c2心肌细胞氧化应激损伤模型,在不同条件下通过实时荧光定量PCR(quantitative real-time PCR,RT-qPCR)检测BI-1的基因表达量,Western blot法检测BI-1的蛋白表达量,激光共聚焦检测BI-1的亚细胞定位。构建BI-1过表达和干扰重组质粒,转染至心肌细胞,观察BI-1表达量的变化、细胞存活率、乳酸脱氢酶活性、半胱天冬酶-3(caspase-3)、半胱天冬酶-9(caspase-9)活性及心肌细胞凋亡率。结果与假手术组比较,缺血再灌注组出现了心肌梗死区,乳酸脱氢酶水平明显升高(P=0.000),BI-1基因和蛋白表达水平随缺血时间或再灌注时间依赖性升高(P<0.01)。在心肌细胞氧化应激损伤模型中,BI-1基因和蛋白表达水平随过氧化氢刺激时间或刺激浓度依赖性升高(P<0.01),过表达BI-1使乳酸脱氢酶的活性降低(P<0.05),心肌细胞的凋亡数下降(P<0.01),抑制了氧化应激所引起的caspase-3、caspase-9活性上升,使细胞存活率升高(P<0.01)。干扰BI-1表达使乳酸脱氢酶的活性升高(P<0.01),细胞存活率下降(P<0.05),心肌细胞的凋亡数增加(P<0.01)。激光共聚焦观察BI-1定位于线粒体上。结论缺血再灌注损伤和氧化应激损伤可促进心肌细胞中BI-1的表达,BI-1能够抑制氧化应激所导致的心肌细胞凋亡,从而起到心肌保护作用。Objective To investigate the role and mechanism of BI-1 in myocardial ischemia-reperfusion injury.Methods Rat models of myocardial ischemia-reperfusion injury and oxidative stress injury of H9c2 cardiomyocytes were constructed.The expression of BI-1 was evaluated by RT-qPCR and Western blot,and subcellular localization of BI-1 was observed by laser confocal microscopy.BI-1 overexpression plasmids and BI-1 shRNA were transfected into H9c2 myocardial cells.BI-1 expression,cell survival rate,activity of LDH,caspase-3 and caspase-9,and apoptotic rate of cardiomyocytes were detected.Results Compared with the sham group,the myocardial infarction area appeared in the I/R group,and the LDH level was significantly increased(P=0.000).Both mRNA and protein level of BI-1 were increased in heart tissues of rats with ischemia-reperfusion injury in a time-dependent manner(P<0.01).In cardiomyocyte oxidative stress injury model,the expression level of BI-1 was increased with H 2O 2 stimulation(P<0.01).Overexpression of BI-1 decreased the activity of LDH(P<0.05)and the number of apoptotic cells(P<0.01),but inhibited the activity of caspase-3,caspase-9 and increased the cell survival rate(P<0.01).Knockdown of BI-1 increased the activity of LDH(P<0.01),decreased the cell survival rate(P<0.05),and increased the number of apoptosis of cardiomyocytes(P<0.01).In addition,BI-1 was located on mitochondria by laser confocal observation.Conclusion Ischemia reperfusion injury and oxidative stress promoted the expression of BI-1 in cardiomyocytes,which could inhibit the apoptosis of cardiomyocytes caused by oxidative stress,exerting a protective role in the myocardium.

关 键 词：心脏缺血-再灌注损伤 Bax inhibitor-1 凋亡 氧化应激损伤 

分 类 号：R542.2[医药卫生—心血管疾病]