LncRNA SNHG7对小鼠心肌梗死后心肌细胞损伤的保护作用

Protective Effect of LncRNA SNHG7 on Myocardial Cell Injury after Myocardial Infarction in Mice

目的探讨长链非编码RNA SNHG7(LncRNA SNHG7)对小鼠心肌梗死后心肌细胞损伤的保护作用及其可能作用机制。方法建立小鼠心肌梗死模型,采用慢病毒方法构建携带SNHG7过表达的慢病毒与携带绿色荧光蛋白(GFP)的慢病毒空载体,随机分为假手术组、模型组、空载组、SNHG7过表达组;缺氧/缺血诱导H9C2细胞建立细胞损伤模型;将正常培养的心肌细胞作为Con组,将缺氧缺血处理的心肌细胞作为缺氧组。采用实时荧光定量聚合酶链反应(qRT-PCR)法检测心肌组织及H9C2细胞中SNHG7、微小RNA-223(miR-223)的表达量;采用脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(TUNEL)检测细胞凋亡;采用qRT-PCR法检测心肌组织中肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、白细胞介素-1β(IL-1β)mRNA的表达量;双荧光素酶报告实验检测SNHG7、miR-223的靶向关系;蛋白质印迹法(Western Blot)检测脂肪酸合成酶(Fas)、Cleaved Caspase-3蛋白表达量。结果与假手术组比较,模型组SNHG7表达水平明显降低(P<0.05),凋亡指数及Fas、Cleaved Caspase-3蛋白水平明显升高(P<0.05),TNF-α、IL-6、IL-1βmRNA表达水平明显升高(P<0.05),SNHG7过表达对细胞凋亡及炎性因子水平的影响与此相反(P<0.05);与Con组比较,缺氧/缺血诱导H9C2细胞SNHG7的表达水平明显降低(P<0.05),miR-223表达水平明显升高(P<0.05)。双荧光素酶报告实验证实SNHG7可靶向结合miR-223,并可负向调控miR-223的表达。结论SNHG7过表达可能通过下调miR-223表达而抑制小鼠心肌梗死后心肌细胞凋亡及炎症反应从而减轻心肌细胞损伤。

Objective To explore the protective effect of long non-coding RNA(LncRNA)SNHG7 on myocardial cell injury after myocardial infarction in mice and its possible mechanism.Methods The mouse myocardial infarction model was established.Lentiviral methods were used to construct lentivirus carrying SNHG7 overexpression and lentiviral empty vector carrying green fluorescent protein(GFP),which were randomly divided into sham operation group,model group,empty group,and SNHG7 overexpression group.Hypoxia/ischemia induced H9C2 cells to establish cell damage models.The cardiomyocytes cultured normally were as Con group,and the cardiomyocytes treated with hypoxia and ischemia were as hypoxia group.The expression levels of SNHG7 and microRNA-223(miR-223)in myocardial tissue and H9C2 cells were detected by quantitative real-time PCR(qRT-PCR)method.Apoptosis was detected by terminal-deoxynucleotidyl transferase mediated nick end labeling(TUNEL)method.The expression levels of tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),and interleukin-1β(IL-1β)mRNA in myocardial tissue were detected by qRT-PCR method.The dual luciferase report experiment was used to detect the targeting relationship between SNHG7 and miR-223.Western Blot was used to detect fatty acid synthetase(Fas)and Cleaved Caspase-3 protein expression.Results Compared with sham operation group,the expression level of SNHG7 in model group decreased(P<0.05),the apoptosis index and the protein levels of Fas and Cleaved Caspase-3 increased(P<0.05),the expression levels of TNF-α,IL-6,and IL-1βmRNA increased(P<0.05),and the effect of SNHG7 over-expression on apoptosis and inflammatory factors was opposite(P<0.05).Compared with Con group,the expression level of SNHG7 in H9C2 cells induced by hypoxia/ischemia decreased(P<0.05),and the expression level of miR-223 increased(P<0.05).The dual luciferase report experiment confirmed that SNHG7 could target and bind to miR-223,and could negatively regulate the expression of miR-223.Conclusion Overexpression of SNHG7 may inhibit myocardial cell apoptosis and inflammation after myocardial infarction by reducing the expression of miR-223,thereby reducing myocardial cell damage.