饮食和运动干预对肥胖大鼠左心室收缩功能的影响

Effect of diet and exercise intervention on left ventricular systolic function in obese rats

目的研究饮食和运动干预对肥胖大鼠左心室收缩功能的影响。方法 3月龄SD大鼠高脂饲料喂养12周建立肥胖大鼠模型,随机分为恢复普通饮食不运动(HFD/NF-S)组、恢复普通饮食运动(HFD/NF-Ex)组、继续高脂饮食不运动(HFD-S)组和继续高脂饮食运动(HFD-Ex)组,跑步训练8周后,记录大鼠一般资料,检测大鼠血脂、血糖。超声心动图测量左心结构和功能,二维斑点追踪技术分析左心室应变和应变率。通过常规和特殊染色,观察大鼠心肌胶原纤维沉积、肥大细胞浸润程度、心肌自噬程度等。电镜下观察大鼠心肌超微结构改变。结果 HFD-S组大鼠相比HFD/NF-Ex组血糖、血脂明显升高(P<0.01),心肌纤维化程度、肥大细胞浸润程度和心肌自噬程度明显增加(P<0.01),室间隔及室壁增厚(P<0.05),各节段应变和应变率减低(P<0.05)。HFD/NF-Ex组相比其他3组各项检查结果均有改善(P<0.05),HFD/NF-S组和HFD-Ex组相比HFD-S组也有改善(P<0.05)但效果不如HFD/NF-Ex组。结论饮食联合运动干预可延缓高脂诱导的肥胖大鼠的心肌重构、心肌纤维化及心肌自噬,纠正心功能。单一运动或饮食干预也可使肥胖大鼠心肌重构、纤维化和自噬程度减轻,改善心功能,但效果不如联合干预组。

AIM To evaluate the effects of diet and exercise intervention on left ventricular systolic function in obese rats. METHODS SD rats were fed with a high fat diet for 12 weeks and obese rats were then randomly divided into 4 groups： normal foodsedentary （HFD/NF-S）, normal foodexercise （HFD/NF-Ex）, high-fat diet-sedentary （HFD-S） and high-fat diet-exercise （HFD-Ex）. After exercise training for 8 weeks, general data of the rats was recorded, blood lipid and blood sugar were detected. Left ventricular structure and function were measured by echocardiography and two-dimensional speckle tracking imaging for analysis of left ventricular strain and strain rate. By routine and special staining, myocardial collagen fibrils, mast cell infiltration, and autophagy were observed in the myocardium. Electron microscope was used to observe ultrastructure changes of the myocardium. RESULTS Compared with in the HFD/NF-Ex group, the rats blood glucose and blood lipid, degree of myocardial fibrosis, mast cell infiltration and autophagy in the HFD-S group increased significantly （P〈0.01）, and ventricular septal and left ventricular wall hypertrophy （P〈0.05）, strain and strain rate of left ventricular segments decreased （P〈0.05）.Compared with the other three groups, the results in the HFD/NF-Ex group were significantly improved. Results in the HFD/NF-S and HFD-Ex group were better than those in the HFD-S group but they were not superior to those in the HFD/NF-Ex group. CONCLUSION The intervention of diet combined with exercise postponed obese rat myocardial remodeling, myocardial fibrosis, and autophagy, which improved cardiac function. Single exercise or diet intervention reduced myocardial remodeling, fibrosis and autophagy in obese rats and improved cardiac function as well, but the effects were not as effective as the combined interventions.