摘要
目的 研究体外心脏震波治疗(CSWT)对心肌梗死(MI)大鼠心肌缺血及心功能的改善作用,探讨CSWT对大鼠心肌血管内皮细胞生长因子表达和心肌纤维化的影响及其机制.方法 采用结扎冠状动脉左前降支的方法建立SD大鼠急性MI模型.MI大鼠按照随机数字表法分为4组:MI组、MI+CSWT组、MI+Y-27632组、MI+Y-27632+CSWT组,每组各6只,另设6只行开胸手术而未结扎左前降支的大鼠为假手术组(Sham组).术后第72天通过超声心动图检测各组大鼠心功能指标.采用HE染色评估心肌病理学形态,Masson染色评估心肌纤维化程度,Ⅷ因子免疫组化染色观察心肌不同区域血管新生情况,免疫印迹法检测MI边缘区细胞外调节激酶(ERK1/2)、肌球蛋白磷酸酶靶亚单位(MYPT1)及促血管新生相关因子如血管内皮细胞生长因子受体2(VEGFR2)、血小板衍生生长因子(PGF)、成纤维细胞生长因子2(FGF2)、血管内皮生长因子A(VEGFA)蛋白表达.结果 (1)术后第72天,与Sham组相比,其余4组大鼠左心室内径、左心室容积增大,左心室壁变薄,辛普森法左心室射血(LVEF)分数降低(均为P＜0.05);MI+CSWT组左心室收缩末期容积和LVEF较MI组改善,MI+Y-27632+CSWT 组 LVEF 较 MI+CSWT 组降低,MI+Y-27632 组 LVEF 高于 MI 组(均为 P＜0.05);(2)在MI边缘区,MI组较Sham组心肌细胞形态不规则、排列紊乱,部分心肌细胞丧失其结构,可见纤维细胞及炎症细胞;MI+CSWT组、MI+Y-27632组及MI+Y-27632+CSWT组细胞形态欠规则,视野内纤维细胞较MI组少;(3)在MI区,Sham组心肌胶原容积分数明显低于其余4组;在MI边缘区,MI+CSWT组心肌胶原容积分数较MI组降低(P＜0.05);(4)MI+CSWT组较MI组p-ERK1/2、p-MYPT1 蛋白表达升高,而 MI+Y-27632+CSWT 组 ERK1/2、p-ERK1/2、p-MYPT1 蛋白表达较 MI+CSWT组降低(均为P＜0.05);MI+CSWT组PGF、FGF2、VEGFA、VEGFR2蛋白表达较MI组高(均为P＜0.05);MI+Y-27632+CSWT 组 PGF、VEGFA、VEGFR2 蛋白表达均低于 MI+CSWT 组(均为 P＜0.05);(5)在MI区,Sham组血管阳性面积高于其余4组(均为P＜0.05);在MI边缘区,MI+CSWT组血管阳性面积较MI组增加,而MI+Y-27632+CSWT组较MI+CSWT组明显下降,MI+Y-27632组血管阳性面积高于MI+Y-27632+CSWT组(均为P＜0.05).结论 CSWT可减少心肌纤维化,促进MI边缘区促血管新生相关因子表达及血管生成,改善心功能,其机制可能与Rho/ROCK/ERK信号通路相关.
Abstract
Objective To evaluate the therapeutic effects of extracorporeal cardiac shock wave therapy(CSWT)on myocardial ischemia and cardiac function in a rat model of myocardial infarction(MI),and to explore the impact of CSWT on the vascular endothelial growth factor expression in rat myocardial cells and myocardial fibrosis,and the associated underlying mechanisms.Methods An MI model of Sprague-Dawley(SD)rats was established by ligating the left anterior descending branch of the coronary artery.The MI rats were randomly divided into four groups according to the random number table method:MI group,MI+CSWT group,MI+Y-27632 group,and MI+Y-27632+CSWT group(each group,n=6).Additionally,six rats that underwent thoracotomy without left anterior descending branch ligation were set as the sham operation group(Sham group).On the 72nd day post operation,echocardiography was performed to evaluate cardiac function in each group of rats.Hematoxylin-eosin(HE)staining was used to evaluate myocardial pathological morphology,Masson staining was used to assess the degree of myocardial fibrosis,factor Ⅷ immunohistochemical staining was used to observe angiogenesis in different myocardial regions,and Western blotting was employed to detect the protein expressions of extracellular regulated kinase(ERK1/2),myosin phosphatase target subunit 1(MYPT1),and angiogenesis-related cytokines such as vascular endothelial growth factor receptor 2(VEGFR2),platelet-derived growth factor(PGF),fibroblast growth factor 2(FGF2),and vascular endothelial growth factor A(VEGFA)in the marginal area of MI.Results(1)On the 72nd day post operation,compared with the Sham group,the left ventricular diameter and left ventricular volume of rats in the other four groups increased,the left ventricular wall became thinner,and the left ventricular ejection fraction(LVEF)decreased(both P＜0.05);left ventricular end-systolic volume and LVEF in MI+CSWT group were improved compared with MI group,LVEF in MI+Y-27632+CSWT group was lower than that in MI+CSWT group,and LVEF in MI+Y-27632 group was higher than that in MI group(both P＜0.05).(2)In the marginal area of MI,the shape of cardiomyocytes in MI group was irregular and disorganized compared with that in Sham group.The cell morphology of MI+CSWT、MI+Y-27632 and MI+Y-27632+CSWT groups was irregular,and there were fewer fiber cells in the field of view than that of MI group.(3)In the MI region,the collagen volume fraction in the Sham group was lower than that in the other four groups;in the MI marginal region,the collagen volume fraction of the MI+CSWT group was lower than that of the MI group(P＜0.05).(4)The expression of p-ERK1/2 and p-MYPT1 proteins was increased in the MI+CSWT group compared with the MI group,while the expression of ERK1/2,p-ERK1/2,and p-MYPT1 proteins was decreased in the MI+Y-27632+CSWT group compared with the MI+CSWT group(all P＜0.05).In the MI+CSWT group,the expression of PGF,FGF2,VEGFA,and VEGFR2 proteins was higher than that in the MI group(all P＜0.05);in the MI+Y-27632+CSWTgroup,the expression of PGF,VEGFA,and VEGFR2 proteins was lower than that in the MI+CSWT group(all P＜0.05).(5)In the MI zone,the positive area of the blood vessels was higher in the Sham group than in the other 4 groups(all P＜0.05);in the MI marginal zone,the positive area of the blood vessels in the MI+CSWT group was increased compared to the MI group,while the positive area in the MI+Y-27632+CSWT group was significantly lower than that in the MI+CSWT group,and the positive area in the MI+Y-27632 group was higher than that in the MI+Y-27632+CSWT group(all P＜0.05).Conclusions CSWT can reduce myocardial fibrosis,promote the expression of angiogenesis-related cytokines and vascular formation in the MI marginal region,improve cardiac function,and its mechanism may involve the Rho/ROCK/ERK signaling pathway.
维普
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