运动训练降低代谢综合征大鼠糖脂代谢的作用及机制

Effects of exercise training on glucose and lipid metabolism in rats with metabolic syndrome

目的观察运动训练对代谢综合征大鼠体质量、尾动脉收缩压、空腹血糖、血脂以及过氧化物酶体增殖物激活受体(PPAR)β/δ基因表达的影响,探讨运动训练改善代谢综合征大鼠糖脂代谢的机制。方法将50只6周龄、体质量160~200g的SD(Sprague Dawley)大鼠随机分成模型组(n=25)和对照组(n=25),并采用高脂高糖饲料制备代谢综合征大鼠模型,模型组和对照组大鼠随机分成运动组和安静组(4组大鼠分别为模型+安静组、模型+运动组、对照+安静组、对照+运动组)。运动组大鼠在动物跑台上运动8周。检测各组大鼠的体质量、内脏脂肪质量、尾动脉收缩压、空腹血糖、血脂以及骨骼肌、脂肪和肝脏组织PPARβ/δmRNA表达量。结果模型组25只大鼠有19只出现代谢综合征变化,模型成功率76%。模型+运动组大鼠的体质量、内脏脂肪质量、三酰甘油和空腹血糖水平明显低于模型+安静组[三酰甘油:(0.70±0.04)比(1.57±0.43)mmol/L;空腹血糖:(5.05±0.30)比(5.63±0.27)mmol/L,均P<0.05]。模型+运动组大鼠的高密度脂蛋白胆固醇(HDL-C)水平明显高于模型+安静组(P<0.05);低密度脂蛋白胆固醇(LDL-C)水平与模型+安静组差异无统计学意义。模型+安静组大鼠的PPARβ/δmRNA表达量较对照+安静组显著降低(均P<0.01)。模型+运动组的PPARβ/δmRNA表达量较模型+安静组上调(P<0.05或P<0.01)。对照+运动组的PPARβ/δmRNA表达量较对照+安静组上调(P<0.01)。结论运动训练能够上调高脂高糖喂食诱导的代谢综合征大鼠的骨骼肌、肝脏、脂肪组织的PPARβ/δ基因表达,这可能是运动训练降低代谢综合征大鼠体质量和改善糖脂代谢的机制之一。

Objective To investigate the effects of exercise training on body mass, tail artery systolic blood pres- sure, fasting blood glucose, blood lipid and the expression of peroxisome proliferator activated receptor （PPAR）β/δ in rats with metabolic syndrome and to explore the related mechanisms. Methods Fifty Sprague Dawley （SD） rats aged six weeks old and weighted 160--200 g were randomly assigned to metabolic syndrome model group （n= 25） and control group （n= 25 ）. Metabolic syndrome model was established by high-fat and high-carbohydrate diets. Rats in model group and control group randomly received exercise or sedentary treatment forming the following four groups： model＋sedentary, model＋exercise, control＋sedentary and control＋exercise. The body weight, visceral fat weight, tail artery systolic blood pressure, fasting blood glucose, blood lipids, and PPARβ/δ mRNA expression in skeletal muscle, adipose tissue and liver tissue were examined after rats exercised on treadmill for 8 weeks. Results Out of 25, 19 rats developed metabolic syndrome with a model success rate of 76%. Compared with rood el＋sedentary treatment group, body weight, visceral fat weight, triglyceride and fasting blood glucose in model＋ exercise group were significantly lower[triglyceride： （0.70±0.04） vs （1.57±0.43） mmol/L, fasting blood glu cose： （5. 05±0.30） vs （5.63±0.27） mmol/L, both P〈0.05] and HDL-C was significantly higher （P〈0.05）, and there was no significant difference in LDL-C level. The expression of PPAR β/δ mRNA in model＋sedentary group decreased significantly compared with control ＋ sedentary group （ all P 〈 0.01 ）. The expression of PPARβ/δ mRNA in model＋ exercise group increased significantly compared with model＋ sedentary group （P〈0.05 or P〈 0.01 ）. The expression of PPARβ/δ mRNA in control＋exercise group decreased significantly compared with control ＋ sedentary group （all P〈0.01）. Conclusion Exercise increases the express of PPARβ/δ mRNA in skeletal muscle, liver, adipose tissue of metabolic syndrome rats. This may be one of the mechanisms by which exercise training reduces body mass and improves glucose and lipid metabolism in rats with metabolic syndrome.