心肌梗死前、后及前后联合运动对大鼠心肌梗死后晚期左心室重构及血流动力学的影响

The Effects of Pre-,Post-MI and Combined Pre-MI and Post-MI Exercise on the Left Ventricular Remodeling and the Hemodynamics of Rats With Myocardial Infarction

目的:研究心肌梗死前、后及前后联合运动对大鼠心肌梗死后晚期左心室重构及血流动力学的影响。方法:将雄性SD大鼠随机分为6组:假手术不运动组(Sed-Sh组)、假手术前运动组(PreE-Sh组)、心肌梗死不运动组(Sed-MI组)、心肌梗死前运动组(PreE-MI组)、心肌梗死后运动组(PostE-MI组)、心肌梗死前后联合运动组(ComE-MI组),每组16只。制作大鼠实验模型,进行血流动力学参数测量,收取心脏。使用Masson染色观察左心室形态、室间隔厚度、心肌梗死范围、左心室游离壁厚度和疤痕厚度。结果:与Sed-Sh组比,PreE-Sh组左心室收缩压(LVSP)、左心室内压最大上升速率(LV+dp/dtmax)、左心室内压最大下降速率(LV-dp/dtmax)均无显著改善(P均>0.05)。与Sed-MI组比,PostE-MI组和ComE-MI组改善了LVSP、左心室舒张末压(LVEDP)、LV+dp/dtmax和LV-dp/dtmax(P均<0.05),而PreE-MI组血流动力学参数有轻微影响,但差异无统计学意义(P>0.05)。另外,PreE-MI组和PostE-MI组之间,血流动力学参数差异均无统计学意义(P均>0.05)。而ComE-MI组LVSP和LV+dp/dtmax明显好于PreE-MI组(P均<0.05)。与Sed-MI组比,PreE-MI组和ComE-MI组显著减少了左心室心肌梗死范围、增加了心脏疤痕厚度(P均<0.05)。结论:心肌梗死前运动减少了心肌梗死范围,增加了疤痕厚度,但是对于心肌梗死晚期血流动力学的改善没有显著影响。而心肌梗死后运动对梗死范围无影响,但是改善了心肌梗死后血流动力学。心肌梗死前后联合运动既减少了心肌梗死范围,改善了左心室重构,又改善了心肌梗死后血流动力学。

Objectives:In this study,we investigated the effects of pre-and Post-MI as well as combined Pre-MI and Post-MI exercise on left Ventricular remodeling and the hemodynamics of rats with myocardial infarction.Methods:Male Sprague–Dawley rats were randomly assigned to six groups(n=16 each):Sedentary sham operation group(Sed-Sh),previous exercise sham operation group(PreE-Sh),sedentary MI group(Sed-MI),previous exercise MI group(PreE-MI),Post exercise MI group(PostE-MI)and combined pre-and post-MI exercise MI group(ComE-MI).Hemodynamic measurements were performed at the end of the experimental protocol,and hearts were sampled for left ventricular histological analysis.Anterior wall thickness,septal wall thickness,scar thickness and infarct area were determined and analyzed on cardiac tissues stained with Masson’s trichrome stain.Results:Compared with Sed-Sh group,tendency of improvement on left ventricular systolic pressure(LVSP),maximum rate of left ventricular pressure rise(LV+dp/dtmax)and maximum rate of left ventricular pressure relax(LV–dp/dtmax)was observed in PreE-Sh group(P>0.05).Compared with Sed-MI group,reduced left ventricular infarct size was significantly reduced,scar thickness was significantly increased in PreE-MI and ComE-MI groups(P<0.05)and LVSP,left ventricular enddiastolic pressure(LVEDP),LV+dp/dtmax and LV–dp/dtmax all improved in PostE-MI and ComE-MI groups(P<0.05),but these parameters remained unchanged in PreE-MI rats(P>0.05).In addition,the differences on hemodynamic parameters were similar between PreE-MI and PostE-MI rats.Compared with PreE-MI and PostE-MI groups,improvement on LVSP and LV+dp/dtmax were more significantly in ComE-MI group.Conclusions:Pre-MI exercise reduced scar size,increased scar thickness,but did not significantly affect hemodynamics late post MI.Post-MI exercise did not reduce scar size and increased scar thickness,also improved hemodynamics late post MI.Combined pre-and post-MI exercise reduced scar size,improved left ventricular remodeling and hemodynamics late post MI.