早期应用沙库巴曲缬沙坦对自发性高血压大鼠急性心肌梗死再灌注心功能及心室重构的影响及机制研究

Effects and mechanism of early application of sacubitril/valsartan on cardiac function and ventricular remodeling in spontaneously hypertensive rats with acute myocardial infarction reperfusion

目的:研究早期应用沙库巴曲缬沙坦(Sacubattril/Valsartan,SAC/VAL)对自发性高血压大鼠急性心肌梗死(acute myocardial infarction,AMI)再灌注心脏重构及心功能的影响。方法:选取60只自发高血压大鼠。随机分为对照组(n=10)和实验组(n=50)。采取结扎冠状动脉的方法建立AMI大鼠再灌注模型;实验组大鼠随机分为三组,分别术后给予安慰剂(Model);预防性给予SAC/VAL与VAL;治疗性给予SAC/VAL与VAL。术后连续观察10周,以ELisa酶联免疫吸附法检测hs-TnT、NT-proBNP、TNF-α、IL-2、IL-6和IL-10等表达水平,以超声心动图测定大鼠LVEDD、LVESD、左心室舒张末容积(left Ventricular end-diastolic volume,LVEDV)、左心室收缩末容积(left ventricular end systolic volume,LVESV)、左心室短轴缩短率(fraction shortening,FS)及LVEF;10周后处死大鼠并以苏木素伊红(HE)染色,Masson染色,并计算胶原容积分数(collagen volume fraction CVF);用Western blot分析法测定心肌组织中p-NF-κB、p-IκB的蛋白水平。结果:(1)与Sham组比较,实验各组大鼠心肌细胞肥大、排列紊乱、纤维化明显,CVF显著升高(P <0.01);hs-TnT、NT-proBNP、TNF-α、IL-2、IL-6表达水平明显升高(P <0.01),IL-10表达水平明显下降(P <0.01);超声心动图测定心脏扩大且收缩功能显著受损(P <0.01)。(2)与Model组比较,用药各组梗死交界区心肌细胞结构相对完整,肌间隙变窄,CVF显著下降(P <0.01);hs-TnT、NTproBNP、TNF-α、IL-2、IL-6水平明显降低(P <0.01),IL-10表达水平明显升高(P <0.01);LVEDD、LVESD、LVEDV、LVESV明显下降(P <0.05),FS、EF值明显增加(P <0.01)。(3)在两组治疗方案中,SAC/VAL和VAL均可改善AMI后大鼠心功能,但SAC/VAL提供了更好的心功能保护,差异具有统计学意义(P <0.01)。(4) P-SAC/VAL组与T-SAC/VAL组比较,CVF减小更加明显,hs-TnT、NT-proBNP、TNF-α、IL-2、IL-6水平明显降低(P <0.01),IL-10表达水平明显升高(P<0.01),LVEDD、LVESD、LVEDV、LVESV明显下降(P <0.01),FS、EF值明显增加(P <0.01)。(5)与Model组比较相比,治疗组心肌组织中磷酸化核因子κB(phosphorylated nuclear factorkappa B,p-NF-κB)、磷酸化κB抑制蛋白(phosphorylated inhibitor of kappa B,p-IκB)表达下调(P <0.05)。结论:(1) SAC/VAL或VAL在AMI再灌注后均可有效改善心室重构、心功能;(2)与VAL相比,SAC/VAL在预防及治疗AMI诱导的心功能障碍方面效果更佳;(3) SAC/VAL早期预防性应用可更好地改善心功能。(4) SAC/VAL可能通过下调p-NF-κB、p-IκB蛋白表达发挥保护心功能的作用。此获益可能与SAC/VAL抑制心肌炎症反应,抑制细胞凋亡,减轻心肌纤维化,改善左心室重构相关。

Objective:To study the effects of Sacubattril/Valsartan(SAC/VAL) on cardiac remodeling and cardiac function in spontaneously hypertensive rats with acute myocardial infarction(AMI) reperfusion.Methods:A total of 60 spontaneously hypertensive rats were randomly divided into control group(n=10) and experimental group(n=50).Control group was the sham operation group,experimental group included the model group,the prophylactic group and the treatment group,the latter two which included SAC/VAL subgroup and VAL subgroup.Results:Compared with the sham group,cardiomyocytes were hypertrophic and fibrotic in all experimental groups,CVF was significantly increased(P<0.01);The five cytokines(hs-TnT,NT-proBNP,TNF-α,IL-2 and IL-6)were significantly increased(P<0.01),while the IL-10 was significantly decreased(P<0.01).echocardiography determined that the heart was enlarged and significantly impaired in systolic function(P<0.01).Compared with model group,the cardiomyocytes were relatively complete and CVF was significantly decreased(P<0.01).Compared with VAL,SAC/VAL provided better protection of cardiac function,the difference was statistically significant(P<0.01).Compared with T-SAC/VAL group,the P-SAC/VAL group showed better improvement in cardiac function and lower pro-inflammatory factors.The expression of p-NF-κB and p-IκB protein was downregulated in the myocardial tissue compared with the Model group(P <0.05).Conclusion:SAC/VAL or VAL can effectively improve ventricular remodeling and cardiac function induced by AMI.Compared with VAL,SAC/VAL is more effective in preventing and treating cardiac dysfunction induced by AMI;The early application SAC/VAL can better improve cardiac function.SAC/VAL may play a protective cardiac function by downregulating phosphorylated nuclear factorkappa B(p-NF-κB),phosphorylated inhibitor of kappa B(p-IκB) protein expression.This benefit of SAC/VAL is likely to be related to inhibit myocardial inflammatory response,inhibiting cell apoptosis,alleviating myocardial fibrosis and improving left ventricular remodeling.