Wang Hui-Bo, Yang Jun, Ding Jia-Wang, Chen Li-Hua, Li Song, Liu Xiao-Wen, Yang Chao-Jun, Fan Zhi-Xin, Yang Jian
Department of Cardiology, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang, China.
Cell Physiol Biochem. 2016;40(5):1163-1174. doi: 10.1159/000453170. Epub 2016 Dec 14.
BACKGROUND/AIMS: Oxidative stress is strongly implicated in the pathogenesis of myocardial damage caused by ischemia reperfusion (I/R). Previous studies have confirmed that cardiac CD47 drives left ventricular heart failure. However, the role for CD47 in myocardial I/R injury (MIRI) has not previously been proposed. This study was designed to investigate whether down-regulation of CD47 using RNA interference (RNAi) technology can relieve inhibition of nitric oxide signaling and attenuate myocardial damage in a rat model of I/R.
Male Sprague-Dawley rats (n = 40) were randomly allocated to four groups and pre-treated either with saline (Sham and I/R groups), or adenovirus expressing either control (Ad-EGFP-N) or CD47-targeting (Ad-EGFP-CD47) RNAi. After four days, the rat MIRI model was established by occluding the left anterior descending coronary artery for 30 min, followed by reperfusion for 3 h. Heart tissue was harvested and assessed by immunohistochemistry, western blot, and quantitative RT-PCR. Outcome measures included infarct size, myocardial enzyme (creatine kinase, creatine kinase-MB, and lactate dehydrogenase) levels in serum, markers of oxidative stress, and morphological changes to the myocardium.
Delivery of Ad-EGFP-CD47 RNAi into the myocardium remarkably decreased CD47 expression levels. Down-regulation of CD47 was significantly associated with reduced infarct size and serum levels of myocardial enzymes, increased activity of endothelial nitric oxide synthase, increased levels of nitric oxide, and decreased levels of oxidative stress.
These data indicate that down-regulation of CD47 exerts a protective effect against MIRI, which may be attributable to attenuation of oxidative stress via activation of the eNOS/NO signaling pathway.
背景/目的：氧化应激与缺血再灌注（I/R）所致心肌损伤的发病机制密切相关。既往研究证实心脏CD47可导致左心室心力衰竭。然而，此前尚未有人提出CD47在心肌I/R损伤（MIRI）中的作用。本研究旨在探讨使用RNA干扰（RNAi）技术下调CD47是否可缓解一氧化氮信号传导的抑制，并减轻I/R大鼠模型中的心肌损伤。
将40只雄性Sprague-Dawley大鼠随机分为四组，分别用生理盐水（假手术组和I/R组）、表达对照（Ad-EGFP-N）或靶向CD47的（Ad-EGFP-CD47）RNAi的腺病毒进行预处理。四天后，通过阻断左冠状动脉前降支30分钟，然后再灌注3小时，建立大鼠MIRI模型。采集心脏组织，通过免疫组织化学、蛋白质印迹和定量RT-PCR进行评估。观察指标包括梗死面积、血清中心肌酶（肌酸激酶、肌酸激酶同工酶MB和乳酸脱氢酶）水平、氧化应激标志物以及心肌的形态学变化。
将Ad-EGFP-CD47 RNAi导入心肌可显著降低CD47表达水平。CD47的下调与梗死面积减小、心肌酶血清水平降低、内皮型一氧化氮合酶活性增加、一氧化氮水平升高以及氧化应激水平降低显著相关。
这些数据表明，下调CD47对MIRI具有保护作用，这可能归因于通过激活eNOS/NO信号通路减轻氧化应激。
