董彦海, 张苗, 崔子慧, 张龙. 右美托咪定预处理通过XIST/miR-125a/DRAM2轴预防大鼠心肌缺血再灌注损伤[J]. 心脏杂志, 2023, 35(5): 503-509. DOI: 10.12125/j.chj.202210035
    引用本文: 董彦海, 张苗, 崔子慧, 张龙. 右美托咪定预处理通过XIST/miR-125a/DRAM2轴预防大鼠心肌缺血再灌注损伤[J]. 心脏杂志, 2023, 35(5): 503-509. DOI: 10.12125/j.chj.202210035
    Yan-hai DONG, Miao ZHANG, Zi-hui CUI, Long ZHANG. Dexmedetomidine preconditioning prevents myocardial ischemia-reperfusion injury in rats via XIST/miR-125a/DRAM2 axis[J]. Chinese Heart Journal, 2023, 35(5): 503-509. DOI: 10.12125/j.chj.202210035
    Citation: Yan-hai DONG, Miao ZHANG, Zi-hui CUI, Long ZHANG. Dexmedetomidine preconditioning prevents myocardial ischemia-reperfusion injury in rats via XIST/miR-125a/DRAM2 axis[J]. Chinese Heart Journal, 2023, 35(5): 503-509. DOI: 10.12125/j.chj.202210035

    右美托咪定预处理通过XIST/miR-125a/DRAM2轴预防大鼠心肌缺血再灌注损伤

    Dexmedetomidine preconditioning prevents myocardial ischemia-reperfusion injury in rats via XIST/miR-125a/DRAM2 axis

    • 摘要:
        目的  探讨右美托咪定(dexmedetomidine,Dex)预处理通过XIST/miR-125a/DRAM2轴对大鼠心肌缺血再灌注损伤(myocardical ischemia-reperfusion injury,MI/RI)的影响。
        方法  体内实验将45只大鼠随机分为假手术组、MI/RI组、Dex组;采用结扎冠状动脉左前降支法建立MI/RI大鼠模型;Dex组缺血前给予静脉注射5 μg/kg Dex预处理;体外实验以H9C2心肌细胞为研究对象,分为空白组、H/R组、Dex组、Dex+pcDNA3.1 NC组、Dex+pcDNA3.1 XIST组;通过缺氧/复氧(hypoxia/reoxygenation,H/R)构建MI/RI体外细胞模型;通过qRT-PCR技术检测体内外实验各组中XIST、miR-125a、DRAM2的mRNA表达水平;通过免疫印迹技术检测体内外实验各组中DRAM2的蛋白表达水平;通过HE染色检测大鼠心肌组织病理学变化和心肌梗死面积;通过ELISA技术检测各组大鼠血清中肌酸激酶同工酶(creatine kinase isoenzyme,CK-MB)、肌钙蛋白I(cTnI)含量;通过丙二醛(malondialdehyde,MDA)、超氧化物歧化酶(superoxide dismutase,SOD)检测试剂盒考察细胞上清液中MDA和SOD的浓度;通过双荧光素酶报告基因系统考察XIST、miR-125a的靶向关系。
        结果  在体内实验中,与假手术组相比,MI/RI组梗死面积、CK-MB、cTnI含量、XIST、DRAM2表达均显著上调(P<0.05),而miR-125a的显著下调(P<0.05);此外,与MI/RI组相比,Dex组梗死面积、CK-MB、cTnI含量、XIST、DRAM2表达均显著下调(P<0.05),miR-125a表达显著上调(P<0.05);在体外实验中,与对照组相比,H/R组MDA含量、细胞凋亡率、XIST、DRAM2表达均显著上调(P<0.05),SOD含量、miR-125a表达均显著下调(P<0.05);与H/R组相比,Dex组MDA含量、细胞凋亡率、XIST、DRAM2表达均显著下调(P<0.05),SOD含量、miR-125a表达均显著上调(P<0.05);过表达XIST逆转了Dex对MIRI体外细胞模型的保护作用(P<0.05)。
        结论  Dex预处理可以改善MIRI大鼠症状,抑制心肌细胞氧化应激损伤及细胞凋亡,可能与调控XIST/miR-125a/DRAM2轴有关。

       

      Abstract:
        AIM  To investigate the effects of dexmedetomidine (Dex) pretreatment on myocardial ischemia reperfusion injury (MI/RI) in rats through XIST/miR-125a/DRAM2 axis.
        METHODS  Forty-five rats were randomly divided into sham operation group, MI/RI group and Dex group. MI/RI rat model was established by ligation of the left anterior descending coronary artery. Dex group was pretreated with intravenous injection of 5 μg/kg Dex before ischemia. H9C2 cardiomyocytes were divided into blank group, H/R group, Dex group, Dex+ pcDNA3.1NC group and Dex+ pcDNA3.1XIST group. In vitro cell model of MIRI was constructed by hypoxia/reoxygenation (H/R). qRT-PCR was used to detect the mRNA expression levels of XIST, miR-125a and DRAM2, Western blotting was used to detect the protein expression of DRAM2 in each group in vivo and in vitro and HE staining was used to detect the myocardial histopathological changes and myocardial infarction size. ELISA was used to determine the contents of creatine kinase isoenzyme (CK-MB) and troponin I (cTnI) in serum of each group and malondialdehyde (MDA) and superoxide dismutase (SOD) detection kit were used to investigate the concentrations of MDA and SOD in the supernatant of cells. The targeting relationship between XIST and miR-125a was investigated by dual luciferase reporter system.
        RESULTS  In vivo, compared with those in sham operation group, infarct size, CK-MB, cTnI content, XIST and DRAM2 expressions were significantly up-regulated (P<0.05), while miR-125a was significantly down-regulated (P<0.05) in MI/RI group. In addition, compared with those in MI/RI group, infarct size, CK-MB, cTnI content, XIST and DRAM2 expressions were significantly down-regulated (P<0.05), while miR-125a expression was significantly up-regulated (P<0.05) in Dex group. In vitro experiments, compared with those in control group, MDA content, apoptosis rate, XIST and DRAM2 expressions were significantly up-regulated (P<0.05), while SOD content and miR-125a expression were significantly down-regulated (P<0.05) in H/R group. Compared with those in H/R group, MDA content, apoptosis rate, XIST and DRAM2 expressions were significantly down-regulated (P<0.05), while SOD content and miR-125a expression were significantly up-regulated (P<0.05) in Dex group. Over-expression of XIST reversed the protective effect of Dex on MIRI cell models in vitro (P<0.05).
        CONCLUSION  Dex pretreatment can improve the symptoms of MIRI rats and inhibit the oxidative stress injury and apoptosis of cardiomyocytes, which may be related to the regulation of XIST/miR-125a/DRAM2 axis.

       

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