严重烧伤早期大鼠心肌收缩性变化及其机制的实验研究

Study on the change in myocardium contractility and its mechanism after severe burns in rats

目的：研究严重烧伤早期心肌收缩性变化及其机制。方法：将６０只大鼠随机分为对照组（１０只，不烧伤）和烧伤组（５０只，致３０％体表面积Ⅲ度烧伤），测定大鼠烧伤前（对照组）及烧伤后１小时、３小时、６小时、１２小时和２４小时心功能及心肌肌球蛋白ＡＴＰ酶活性变化。结果：烧伤组左心室收缩压（ＬＶＳＰ）和左心室收缩压最大变化速率（±ｄｐ／ｄｔｍａｘ）比对照组明显降低；心肌肌球蛋白ＡＴＰ酶活性比对照组大幅度下降，与ＬＶＳＰ和ｄｐ／ｄｔｍａｘ均呈显著正相关（ｒ＝０．９１７２，ｒ＝０．９７６１；Ｐ均＜０．０１）。结论：心肌肌球蛋白ＡＴＰ酶活性降低是严重烧伤早期心肌收缩性减弱的重要机制之一。

Objective:To investigate the change in myocardium contractility and its mechanism during early postburn stage.Methods:Rats were divided into control group (n=10,without burns)and burn group (n=50,30% TBSA fullthickness burns).Changes in myocardial myosinATP ase activtities and cardiac contractile function were measured in controls,and at 1,3,6,12,24 hours postburn.Results:The left ventricular systolic pressure and maximal rate of the change of left intraventricular pressure (±dp/dtmax) in burned group were markedly lower than those in control group,and myocardial myosinATPase activities were also decreased in burn group.Also,a significant positive correlation was found between myosinATPase activity and LVSP or dp/dtmax(r=0917 2,r=0976 1;both P<001).Conclusions:The reduction in myocardial myosinATPase activity may be one of the important mechanisms in cardiac dysfunction during early postburn stage.