巨噬细胞移动抑制因子基因沉默对急性心肌梗死大鼠心功能的影响及机制

Effects of macrophage migration inhibitory factor gene silencing on cardiac function in rats with myocardial infarction

目的观察巨噬细胞移动抑制因子(MIF)基因沉默对急性心肌梗死(AMI)大鼠心功能的影响,并探讨其机制。方法将40只清洁级SD大鼠随机分为假手术组、生理盐水组、Adv-空白载体组和Adv-siRNA-MIF组,每组10只。采用结扎左冠状动脉前降支的方法构建AMI模型,Adv-siRNA-MIF组在左心室游离壁注射siRNA-MIF重组腺病毒,生理盐水组和Adv-空白载体组同法分别注射等量生理盐水和空白腺病毒载体。建模14 d后,超声检查大鼠心功能,HE染色观察大鼠心肌组织形态学变化,TUNEL法检测大鼠心肌细胞凋亡情况,Western blotting法检测大鼠心肌组织中的MIF蛋白,实时荧光定量PCR法检测大鼠心肌组织中的MIF、单核细胞趋化蛋白1(MCP-1)、白细胞介素1β(IL-1β)、IL-6、IL-8和TNF-αmRNA。结果与生理盐水组和Adv-空白载体组比较,Adv-siRNAMIF组大鼠左心室舒张末期内径、左心室收缩末期内径均降低而左心室射血分数升高,心肌细胞损伤及凋亡指数降低,心肌组织中MIF蛋白和mRNA以及MCP-1、IL-1β、IL-6、IL-8和TNF-αmRNA相对表达量均降低(P均<0.05)。结论重组腺病毒载体介导的MIF基因沉默可有效改善AMI大鼠心功能,其机制可能与抑制炎症反应从而减少心肌细胞凋亡有关。

Objective To observe the effects of macrophage migration inhibitory factor （MIF） gene silencing on cardiac function in rats with myocardial infarction and to investigate its possible mechanism.Methods Forty clean-grade SD rats were randomly divided into the sham operation group, saline group, Adv-blank vector group, and Adv-siRNA-MIF group, with 10 in each group. AMI model was constructed by ligation of left anterior descending coronary artery. We injected siRNA-MIF recombinant adenovirus vector into the left ventricular free wall of rats in the Adv-siRNA-MIF group, while in the saline group and Adv-blank vector group, rats were given the same amount of physiological saline and blank adenovirus vector. After modeling of 14 d, the heart function of each group was detected by using ultrasound. The morphological changes of myocardial tissues in each group were observed by HE staining. TUNEL method was used to detect the cardiomyocyte apoptosis in each group. Western blotting was used to detect the expression of MIF protein in myocardial tissues of rats in each group. The expression of MIF, MCP-1, IL-1β, IL-6, IL-8 and TNF-α mRNA in the myocardial tissues of rats in each group was detected by real-time fluorescent quantitative PCR.Results Compared with the saline group and Adv-blank vector group, left ventricular end diastolic diameter and left ventricular end-systolic diameter decreased, the left ventricular ejection fraction increased, the cardiomyocyte injury and apoptotic index of cardiomyocytes decreased, the relative expression levels of MIF protein and mRNA, and the relative expression levels of MCP-1, IL-1β, IL-6, IL-8 and TNF-α mRNA decreased in the Adv-siRNA-MIF group （all P 〈0.05）.Conclusion Recombinant adenovirus vector-mediated MIF gene silencing can effectively improve cardiac function in rats with AMI by inhibiting the inflammatory response and thereby reducing myocardial apoptosis.