代谢综合征大鼠左心室外膜收缩功能不全与心外膜脂肪小窝蛋白-1表达降低平行出现

摘要

目的:探讨代谢综合征大鼠心脏收缩功能及心外膜脂肪小窝蛋白-1表达的改变.方法:16只6周龄雄性SD大鼠随机分为代谢综合征模型组及对照组.模型大鼠给予小剂量链脲佐菌素、N-硝基-L-精氨酸甲酯盐酸盐联合高脂、高盐、高糖饲养6周.实验开始及结束时测定大鼠的体重、空腹血糖、胰岛素、血脂、口服糖耐量及血压水平,超声检测大鼠左心室射血分数及应变指数.实验结束时分离心外膜脂肪检测小窝蛋白-1的表达.结果:6周后,模型大鼠体重[(462±31.6)g比(406±49.4)g]、空腹胰岛素[(5.47±2.26)ng/mL比(2.69±0.61)ng/mL]、口服糖耐量曲线下面积[(1544.6±502.2)mg/(L·min)比(911.0±69.8)mg/(L·min)]、甘油三酯[(0.66±0.44)mmol/L比(0.28±0.07)mmol/L]、总胆固醇[(1.71±0.43)mmol/L比(1.01±0.29)mmol/L]及低密度脂蛋白水平[(0.66±0.25)mmol/L比(0.22士0.08)mmol/L]、收缩压[(163.0±26.0)mmHg比(117.5±11.5)mmHg]及舒张压[(121.8±15.5)mmHg比(90.5±16.6)mmHg]均高于对照组(P<0.05),而空腹血糖及高密度脂蛋白水平与对照组比较无明显差异(P>0.05).左心室外膜收缩期周向应变及应变率均低于对照组[(-7.20±1.46)%比(-9.87±1.93)%],[-1.56±0.35)1/s比(-2.19±0.49)1/s;均P<0.05].模型大鼠心外膜脂肪小窝蛋白-1的表达明显低于对照组.结论:代谢综合征大鼠左心室外膜收缩功能不全与心外膜脂肪小窝蛋白-1表达降低平行出现.%Objective To explore the alterations of systolic cardiac function and expression of caveolin-1 in epicardial adipose tissue (EAT) in metabolic syndrome (MS) rats. Methods Sixteen six week-old male SD rats were divided into MS model and control group randomly. MS model rats were intervened with low-dose streptozocin and L-arginine methyl ester, and fed with high-fat, high-salt and high-glucose diet for six weeks. Body weight, fasting plasma glucose (FPG), fasting insulin (FINS), plasma lipids levels, oral glucose tolerance test (OGTT) and blood pressure were examined at the beginning and the end of the study respectively. Left ventricular ejection fraction and strain indexes were evaluated with echocardiography. EAT was isolated and expression of caveolin-1 was tested at the end of the study. Results Body weight[(462 ± 31.6) vs (406 ± 49.4)g], areas under the curve of OGTT[(1544.6 ± 502.2) vs (911.0 ± 69.8) mg/(L-min)], levels of FINS[(5.47 ± 2.26) vs (2.69 ± 0.61)ng/ mL], triglyceride [ (0.66 ± 0.44) vs (0.28 ± 0.07)mmol/L], total cholesterol [(1.71 ± 0.43) vs (1.01 ± 0.29) mmol/L] and low-density lipoprotein [(0.66 ± 0.25) vs (0.22 ± 0.08)mmol/L], systolic and diastolic blood pressure [(163.0 ± 26.0) vs (117.5 ± 11.5)mmHg, (121.8 ± 15.5) vs (90.5 ± 16.6) mmHg] in MS model rats were all significantly higher than that of the controls (P < 0.05), while no differences in FPG [(5.15 ± 2.35) vs (5.76 ± 0.73)mmol/L] and high-density lipoprotein levels [(0.72 ± 0.20) vs (0.83 ± 0.18)mmol/L] were found between two groups (P > 0.05) after being fed for six weeks. Left ventricular systolic epicardial circumferential strain and strain rate in MS model rats were significantly lower than that of the controls [(-7.20 ± 1.46)% vs (- 9.87 ± 1.93)%, (-1.56 ± 0.35) vs (-2.19 ± 0.49) 1/s, P < 0.05]. Expression of caveolin-1 in EAT in MS rats was significantly lower than that of the controls at the end of the study. Conclusion Left ventricular epicardial systolic cardiac dysfunction paralleled with low expression of caveolin-1 of EAT in MS model rats.