饮食结构变化诱导SD大鼠肥胖及血压变化的机制

Mechanism of the change of blood pressure in rat model of high-fat diet-induced obesity

目的了解饮食结构变化对正常大鼠代谢及血压的影响及其可能机制。方法雄性Sprague-Dawley(SD)大鼠40只随机分为高脂组和对照组。以脂肪占热卡53%饮食喂养5、10周,观察实验大鼠收缩压、体质量、腹部脂肪量和空腹血糖、血脂及胰岛素水平等代谢指标的变化。结果高脂组收缩压均高于对照组[5周组(105.506±4.634)mmHgvs.(100.060±4.773)mmHg,P<0.05;10周组(108.555±3.948)mmHgvs.(101.485±4.223)mmHg,P<0.01];高脂组大鼠体质量、腹部脂肪量及代谢指标均明显高于对照组,而胰岛素敏感性降低。多元相关分析显示大鼠收缩压(SBP)随体质量、空腹血糖(FPG)、空腹胰岛素(FINS)、游离脂肪酸(FFA)、甘油三酯(TG)、总胆固醇(TC)等增加而升高;大鼠血FFA与SBP、腹部脂肪占体质量的百分含量(Vfat%)、FINS、FPG、TG等呈正相关,与胰岛素敏感指数(ISI)呈负相关。结论高脂饮食可导致正常大鼠肥胖、代谢紊乱及血压升高;血游离脂肪酸升高可能为其糖脂代谢紊乱与血压升高的联系点。

Objective To investigate the influence of high-fat diet on blood pressure and metabolism in Sprague-Dawley （SD） rats and its mechanism. Methods Forty male SD rats were randomly divided into 4 groups which were fed with a diet containing 53% calorie as fat（HF） or a normal diet（ND） for 5 or 10 weeks. Systolic blood pressure （SBP）, body weight, abdominal adipose tissue, blood lipids, fasting insulin （FINS）, and fasting plasma glucose （FPG） were measured after 5 and 10 weeks respectively. Results SBP of HF groups were higher than that of NDgroups [HF5 vs. ND5, （105.506±4.634）mmHg vs. （100.060±4.773）mmHg, P〈0.05; HF10 vs. ND10, （108. 555±3.948）mmHg vs. （101.485±4.223）mmHg, P〈0.01]. Body weight, free fatty acids （FFA）, triglycerides（TG）, FPG and FINS increased and insulin sensitivity index（IS1） decreased more significantly in HF groups than that in ND groups （P〈0.05）. Multivariate correlation analysis revealed that SBP was elevated with the increase of body weight, FPG, FINS, FFA, TG and TC. FFA was positively correlated with SBP, Vfat%, FPG and FINS, but negatively with ISI. Oonclusion High-fat diet can induce obesity, metabolic disorder and the elevation of SBP in SD rats. High FFA can decrease insulin sensitivity and it might be the connection between metabolic dysfunction and the blood pressure elevation.