间歇低压低氧预处理对心肌缺血/再灌注损伤及ZFP580表达的影响

The effects of intermittent hypobaric hypoxia on myocardial ischemia /reperfusion injury and ZFP580 expression

目的:探讨间歇性低压低氧(IHH)预处理对大鼠心肌缺血/再灌注(I/R)损伤后血清中心肌酶、心肌梗死的影响及锌指核转录因子ZFP580发挥的作用。方法:32只雄性Wistar大鼠随机分为IHH预处理组和常氧对照组(n=16)。IHH组大鼠置于模拟海拔高度为5 000 m的低压氧舱中,每天6 h,持续42 d。两组大鼠经结扎冠状动脉左前降支建立心肌I/R损伤模型后,检测血清中乳酸脱氢酶(LDH)活性及肌酸磷酸肌酶同功酶(CK-MB)浓度,并利用Western blot方法观察各组大鼠心肌组织中ZFP580的表达情况。每组另外8只大鼠经心肌酞菁蓝-TTC染色后比较心肌梗死面积。培养大鼠H9c2心肌细胞,利用慢病毒介导的基因转染实验获得高表达ZFP580的心肌细胞,并进行心肌细胞模拟缺血/再灌注(SI/R)损伤实验。利用Annexin V-PE/7-AAD染色及流式细胞术检测H9c2心肌细胞的凋亡情况。结果:IHH预处理能明显减少心肌I/R损伤后LDH、CK-MB漏出至血清,并明显缩小心肌梗死面积。大鼠经IHH预处理后心肌组织中ZFP580的表达上调,IHH预处理明显上调心肌I/R损伤后心肌组织中ZFP580的表达。高表达ZFP580的H9c2心肌细胞在SI/R损伤后细胞凋亡率明显下降。结论:IHH预处理对于心肌I/R损伤具有明显细胞保护作用,其上调的ZFP580表达具有减少心肌细胞凋亡的作用,ZFP580可能作为心肌细胞内源性抗凋亡分子之一,参与IHH预处理抗心肌I/R损伤的过程。

Objective： To elucidate whether ZFP580 is involved in the cardioprotective effects of intermittent hypobaric hypoxia （IHH） a- gainst myocardial ischemia/reperfusion （I/R） injury. Methods： Thirty two male Wistar rats were randomly divided into 2 groups（ n = 16）： normoxia control group and IHH preconditioning group. Rats in IHH group were exposed in a hypobaric chamber （equivalent to an altitude of 5 000 m） for a 6 h period each day for 42 d. Plasma was collected and lactate dehydrogenase （LDH） and creatine kinase-MB （CK-MB） were measured after 2 h of myocardial I/R injury. ZFP580 protein expression in myocardial tissue was assayed by Western blot. Other 8 rats in each group were used to evaluate I/R-induced cardiac infarction by TIC staining. Lentivirus-mediated gene transfection was performed in H9c2 cells 72 h prior to simulated ischemia/reperfusion （SI/R） exposure. The degree of cell apoptosis was determined by annexin V/7-AAD staining and flow cytometry analysis. Results： Compared with normoxia control group, adaptation to IHH attenuated infarct size and plasma leakage of LDH and CK-MB. In addition, ZFP580 expression in the myocardium was up-regulated by IHH. The results of gene transfection showed that ZFP580 overexpression significantly inhibited cells apoptosis induced by SI/R. Condusion： Our findings demonstrate that the cardioprotective effect of IHH against I/R injury is mediated via ZFP580, a novel transcription factor, with anti-apoptotic roles in myocardial cells.