左西孟旦减轻模型大鼠离体心脏停灌/再灌注损伤

Levosimendan attenuates suspension-reperfusion injury in isolated hearts of rat models

目的探讨左西孟旦对大鼠离体心肌停灌/再灌注过程中环磷酸鸟苷-腺苷酸合成酶/干扰素基因刺激因子(cGAS-STING)信号通路的影响。方法将大鼠分为持续灌注组(CO组)、停灌/再灌注组(SR组)、停灌/再灌注+左西孟旦组(SR-L组)及停灌/再灌注+左西孟旦+STING激活剂DMXAA组(SR-LD组)。分别在平衡灌注末(T0)、再灌注30 min(T1)和再灌注60 min(T2)时记录心率(HR)、左室舒张末压(LVEDP)、左室发展压(LVDP)、左室内压最大上升速率(+dp/dt_(max))和左室内压最大下降速率(-dp/dt_(max))和再灌注心律失常评分分数。Western blot检测cGAS-STING信号通路及自噬相关蛋白表达,氯化三苯基四氮唑(TTC)染色法测定心肌梗死面积百分比。结果与CO组相比,SR组T1、T2时HR、LVDP、+dp/dt_(max)和-dp/dt_(max)降低,LVEDP升高,再灌注心律失常评分增加,心肌梗死面积百分比增加,心肌组织cGAS、STING蛋白表达升高,LC3Ⅱ/Ⅰ比值升高,p62降低(P<0.05);与SR组比较,SR-L组心功能指标改善,心肌组织cGAS、STING蛋白表达下调,LC3Ⅱ/Ⅰ比值降低,p62升高(P<0.05);与SR-L相比,SR-LD组逆转了左西孟旦对心肌损伤的保护作用。结论左西孟旦可能通过抑制cGAS-STING信号通路及下调心肌细胞自噬,改善心功能,减少心肌梗死面积,从而发挥心肌保护作用。

Objective To investigate the effect of levosimendan on the cyclic guanosine monophosphate-adenosin monophosphate synthase-interferon gene stimulating factor(cGAS-STING)signaling pathway during suspension-reperfusion in isolated rat myocardium.Methods The rats were divided into four groups(n=12)using random number table:continuous perfusion group(CO group),suspension-reperfusion group(SR group),suspension-reperfusion+levosimendan group(SR-L group),and suspension-reperfusion+levosimendan+STING activator:DMXAA group(SR-LD group).Heart rate(HR),left ventricular end-diastolic pressure(LVEDP),left ventricular developmental pressure(LVDP),maximum rate of increase in left ventricular pressure(+dp/dt_(max))and maximum rate of decrease in left ventricular pressure(-dp/dt_(max)),and Reperfusion Arrhythmia scores were recorded at the end of equilibrium perfusion(T0),30 min of reperfusion(T1),and 60 min of reperfusion(T2)respectively.Western blot was used to detect cGAS-STING signaling pathway and autophagy-related protein expression.The size of myocardial infarction was measured by using triphenyl tetrazolium chloride(TTC).Results Compared with CO group,SR group had decreased HR,LVDP,+dp/dt max,and-dp/dt max at T1 and T2,increase of LVEDP,Reperfusion Arrhythmia score,percentage of myocardial infarcted area,expression of myocardial tissue cGAS and STING proteins and increased LC3Ⅱ/Ⅰratio,while p62 decreased(P<0.05);compared with SR group,SR-L group cardiac function indexes improved,myocardial tissue cGAS,STING protein expression was down-regulated,LC3Ⅱ/Ⅰratio was decreased,and p62 was elevated(P<0.05);SR-LD group reversed the improvement of myocardial injury by levosimendan compared with SR-L.Conclusions Levosimendan may protect myocardial tissue by inhibiting the cGAS-STING signaling pathway,down-regulating cardiomyocyte autophagy and reducing myocardial infarction size,so to improve cardial function.