miR-146a减轻心肌缺血/再灌注损伤(MI/RI)大鼠的心肌细胞凋亡

摘要/Abstract

摘要： 目的探究miR-146a对心肌缺血/再灌注损伤(MI/RI)大鼠血清心肌酶谱水平、Toll-样受体4(TLR4)基因及心肌细胞凋亡作用机制。方法将36只大鼠分为假手术组(sham)、模型组(model)、miR-146a NC组(结扎后转染miR-146a-NC)、miR-146a agomir组(结扎后转染miR-146a-a agomir)。通过TTC染色法评估心肌梗死面积;RT-qPCR检测心肌组织miR-146a/TLR4 mRNA表达;TUNEL染色检测心肌组织心肌细胞凋亡;比色法检测血清中乳酸脱氢酶(LDH)、肌钙蛋白(cTnT)、肌酸激酶同工酶(CK-MB)活性;免疫印迹检测心肌组织中TLR4蛋白表达。结果模型组与假手术组相比,心肌梗死区域(白色)面积增加(P＜0.05),与模型组相比,miR-146a agomir组心肌梗死区域(白色)面积降低(P＜0.05);模型组与假手术组相比miR-146a mRNA表达降低(P＜0.05),与模型组相比,miR-146a agomir组miR-146a mRNA表达升高(P＜0.05);模型组与假手术组相比,心肌肌纤维断裂肿胀、间质充血明显、结构消失、细胞多处坏死界限不清;与模型组相比,miR-146a agomir组心肌组织排列整齐,水肿等病理均改善;模型组与假手术组相比,血清中LDH、cTnT、CK-MB活性、心肌细胞凋亡率及TLR4、肿瘤坏死因子-α(TNF-α)、核因子-κB(NF-κB)蛋白表达均升高(P＜0.05),与模型组相比,miR-146a agomir组上述指标均降低(P＜0.05)。结论 miR-146a在MI/RI的心肌组织中呈现低表达,过表达可降低血清心肌酶谱活性及TLR4表达,从而减少心肌细胞凋亡保护心脏。

关键词: 心肌缺血/再灌注, 心肌酶谱, 凋亡, 心肌组织

Abstract: Objective To investigate the mechanism of miR-146a on the level of serum myocardial enzyme, Toll-like receptor 4 (TLR4) genes and apoptosis of myocardial cells in rats with myocardial ischemia-reperfusion injury (MI/RI). Methods Thirty-six rats were divided into sham operation group (sham), model group (model), miR-146a NC group (transfected with miR-146a-NC after ligation) and miR-146a agomir group (transfected with miR-146a-a agomir after ligation).Myocardial infarct size was measured by TTC staining, the mRNA expression of miR-146a/TLR4 in myocardial tissue was detected by RT-qPCR and cardiomyocyte apoptosis was microscopied by TUNEL staining.The activity of lactate dehydrogenase (LDH), troponin (cTnT) and creatine kinase isoenzyme (CK-MB) in serum was determined by colorimetry.TLR4 protein expression in myocardial tissue was detected by Western blot. Results Compared with sham operation group, the area of myocardial infarction (white) in model group was increased (P＜0.05). While the area of myocardial infarction (white) in miR-146a agomir group decreased (P＜0.05), and the mRNA expression of miR-146a in the model group was decreased (P＜0.05), the miR-146a mRNA expression was increased in miR-146a agomir group (P＜0.05);Compared with the sham operation group, the myocardial muscle fibers were broken and swollen, the interstitial hyperemia was obvious, the structure disappeared, and the boundary of multiple cell necroses was not clear.Compared with the model group, the myocardial tissues of miR-146a agomir group were neatly arranged, and pathology such as edema was improved, the activities of LDH, cTnT and CK-MB, the apoptosis rate of myocardial cells and the protein expressions of TLR4, tumor necrosis factor-α (TNF-α) and nuclear factor-κB (NF-κB) in serum of the model group were increased (P＜0.05).Compared with model group, the above indexes in miR-146a agomir group were decreased (P＜0.05). Conclusions The expression of miR-146a is low in the myocardial tissue of MI/RI, and over-expression can reduce the activity of serum myocardial enzyme spectrum and TLR4 expression, thereby reducing the apoptosis of cardiomyocytes and protecting the heart.

Key words: myocardial ischemia-reperfusion, myocardial enzyme spectrum, apoptosis, myocardial tissue

中图分类号:

R542.3

郑新, 于海波. miR-146a减轻心肌缺血/再灌注损伤(MI/RI)大鼠的心肌细胞凋亡[J]. 基础医学与临床, 2021, 41(12): 1756-1761.

ZHENG Xin, YU Hai-bo. miR-146a alleviates apoptosis of myocardial cells in rats with myocardial ischemia-reperfusion injury[J]. Basic & Clinical Medicine, 2021, 41(12): 1756-1761.

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