拮抗内源性孤啡肽可通过下调microRNA-1途径抑制大鼠再灌注性心律失常

目的研究内源性孤啡肽(N/OFQ)对大鼠再灌注性心律失常(RA)的影响,以及microRNA-1(miR-1)在其中的作用。方法将SD大鼠随机分为3组,即假手术组(Sham组)、缺血/再灌注组(I/R组)及孤啡肽受体拮抗剂(UFP-101)预处理组(U+I/R组),每组8只。通过结扎左冠状动脉前降支制备大鼠缺血/再灌注模型,记录各组大鼠再灌注期间心律失常的发生情况并对其进行评分;采用qRT-PCR法检测miR-1、GJA1及KCNJ2基因表达水平;采用Western blot法检测Cx43、kir2.1蛋白表达情况。结果拮抗内源性N/OFQ可明显降低大鼠RA及致心律失常评分(P<0.01)。qRT-PCR及Western blot结果提示,与Sham组相比,I/R组miR-1表达增多(P<0.01),而Cx43及其mRNA表达下降(P<0.05),kir2.1表达下降(P<0.01);与I/R组比较,U+I/R组miR-1表达下降(P<0.05),Cx43及kir2.1表达增多(P<0.05)。结论内源性N/OFQ可上调miR-1,使Cx43及kir2. 1蛋白表达受到抑制,从而导致缺血/再灌注性心律失常。

Antagonism of endogenous nociceptin/orphanin FQ inhibits reperfusion-induced arrhythmias by down-regulating microRNA-1 in rats

Aim To investigate the effect of endogenous nociceptin/orphanin FQ(N/OFQ) on arrhythmias induced by myocardial ischemia/reperfusion(I/R) in rats and the role of microRNA-1(miR-1) in it.Methods Twenty-four Sprague-Dawley rats were randomly divided into sham-operation group(Sham group),ischemia/reperfusion group(I/R group) and the pretreatment of N/OFQ receptor antagonist(UFP-101) group(U+I/R group).The model of myocardial ischemia/reperfusion was prepared by ligating the left anterior descending branch of the coronary artery of rats.The incidence and arrhythmogenic scores during reperfusion in rats were recorded and analysed.The myocardium at the risk of ischemia was collected at 120 min after reperfusion.MiR-1,GJA1 and KCNJ2 levels were detected by qRT-PCR and Cx43 and kir2.1 protein levels were detected by Western blot.Results Antagonism of endogenous N/OFQ could significantly reduce reperfusion arrhythmias and arrhythmogenic scores,compared with I/R group( P <0.01).The qRT-PCR and Western blot results suggested that compared with sham group,miR-1 expression significantly increased in I/R group( P <0.01),while the expression of Cx43,Cx43 mRNA and kir2.1 decreased( P <0.05);compared with I/R group,pretreatment with UFP-101 led to reduction of miR-1( P <0.05) and rise of Cx43 and kir2.1( P <0.05).Conclusions Endogenous N/OFQ up-regulates miR-1 and inhibits the expression of Cx43 and kir2.1 proteins,leading to reperfusion arrhythmias in rats.