饮食和运动干预对高脂饮食性肥胖大鼠心肌间质重构及MMP-2活性的影响

Effects of dietary and athletic intervention on cardiac interstitial remodeling and MMP-2 activities in high fat-fed obese rats

目的研究饮食和运动干预对肥胖大鼠心脏间质重构及MMP-2活性的影响。方法将21日龄SD大鼠随机分为正常组和高脂喂养组,后者在第8周时选取体重超出正常对照组平均体重20%者为肥胖大鼠,再分为肥胖对照组、饮食干预组和饮食与运动联合干预组,第16周时处死。超声心动图测量心脏结构,羟普氨酸法测定心肌胶原含量,明胶酶谱法测定心肌MMP-2活性。结果肥胖大鼠存在严重的血脂紊乱,左心室肥厚,心肌胶原含量显著增加,MMP-2活性增强。饮食干预组血脂紊乱程度减轻、心室肥厚减轻,而心肌胶原和MMP-2活性无明显变化。饮食与运动联合干预组体重下降更明显,但左室肥厚显著,胶原含量和MMP-2活性无变化。结论高脂饮食性肥胖大鼠存在心脏间质重构,并与MMP-2活性改变有关。单纯饮食疗法可减缓心肌重构的进展,饮食与运动联合干预可使心肌重构早期良性逆转。

Objectives To explore the effects of dietary intervention and physical activity on cardiac structure, collagen contents and MMP-2 activities of high fat-fed obese rats. Methods Twenty-one days old SD rats were randomly divided into two groups, high fat-fed group and control group. After 8 weeks, the rats in high fat-fed group with body weight of at least 20% more than the mean weight of control group were selected and randomly subdivided into obese control group, obese diet-control group and obese diet-control plus exercise group. All rats were sacrificed in the 16th week. Cardiac structural indexes were determined by ultrasound cardiography. Myocardial collagen content was evaluated by quantitative determination of hydroxyproline. MMP-2 activity was measured by SDS-PAGE zymography. Results In high fat-fed obese rats, there were severe hyperlipidemia and left ventricular mass increase along with elevated collagen content and MMP-2 activity. In diet-control group, the hyperlipidemia and left ventricular mass increase were alleviate. However, there were no obvious changes in the collagen content and MMP-2 activity. In diet-control plus exercise group, the body weight decreased further while the left ventricular mass increased. No changes were observed in the collagen content and MMP-2 activity. Conclusions There were left ventricular mass and myocardial collagen content increase in high fat-fed obese rats, which might be related with the activity of MMP-2. Dietary intervention could slow down the progression of ventricular reconstitution. Dietary intervention combined with physical activity might benefit the ventricular remodeling.