大鼠心肌梗死模型中心肌组织胶原代谢变化对心室重塑的意义

Significance of metabolic changes of myocardial collagens in rat myocardial infarction model during ventricular remodeling

目的:观察大鼠心肌梗死模型胶原的变化规律,认识心室重塑及心脏功能变化的机制。方法:实验选用SD大鼠68只,随机将其分为对照组(n=10)、手术对照组(n=10)、心肌梗死后1d组(n=12)、心肌梗死后1周组(n=12)、心肌梗死后2周组(n=12)、心肌梗死后4周组(n=12)。通过结扎68只SD大鼠冠状动脉前降支建立心肌梗死模型。分别于术后第1天,及1,2,4周取心肌组织,采用羟脯氨酸消化法和免疫组化分别测定胶原总量和Ⅰ/Ⅲ胶原比例变化。结果:心肌梗死后2,4周组大鼠心肌Ⅰ/Ⅲ胶原比例(2.12±0.62,2.18±0.71)明显高于对照组(2.71±0.30)(t=2.84,2.79,P<0.05)。心肌梗死后2,4周组大鼠心肌胶原犤(37.16±2.67),(38.19±1.41)mg/g犦明显高于对照组犤(35.61±1.52)mg/g犦(t=3.12,5.23,P<0.01)。手术对照组、心肌梗死后1d、1周组与对照组大鼠心肌胶原含量、Ⅰ/Ⅲ胶原比例比较,差异无显著性意义(P>0.05)。结论:SD大鼠心肌梗死后心肌组织内胶原总量增加,Ⅰ/Ⅲ胶原比例减少,这种胶原代谢变化规律是心室重塑发生机制重要组成部分。

AIM:To observe the changing characteristics of collagen in rat myocardial infarction(MI) models and comprehend the mechanisms of ventricular remodeling and cardiac function changes. METHODS:Sixty-eight SD rats were randomly divided into the groups of control(n=10),operation control(n=10),one day after MI(n=12),one week after MI(n=12),two weeks after MI (n=12) and four weeks after MI(n=12).The descending left coronary artery of the 68 rats was ligated to produce a MI model.Myocardial tissues were excised at day 1,week 1,2 and 4 post-MI.The total amount of collagen and the ratio of Ⅰ/Ⅲcollagen were assessed by the method of chloramine T and immunohistochemical staining respectively. RESULTS:The ratio of Ⅰ/Ⅲmyocardial collagen of rats in the groups of 2 weeks and 4 weeks after MI was 2.12±0.62 and 2.18±0.71 respectively,significantly higher than that in the control group(2.71±0.30)(t=2.84,2.79,P< 0.05).The myocardial collagen of rats in the groups of 2 weeks and 4 weeks after MI[(37.16±2.67) and (38.19±1.41) mg/g respectively] was also significantly higher than that in the control group[(35.61 ±1.52) mg/g](t=3.12,5.23,P< 0.01).The collagen amount and the ratio of Ⅰ/Ⅲin the myocardium of rats were insignificantly different in the groups of operation control,1 day after MI,1 week after MI and control(P >0.05). CONCLUSION:After MI in SD rats,collagen amount increases and the ratio of I/III decreases during myocardial tissues.Such changing characteristics of collagen metabolism are the major causes of ventricular remodeling.