高脂饮食对Wistar和GK大鼠糖脂代谢及胰岛素分泌功能的影响

Effects of high-fat diet on carbohydrate,lipid metabolism and insulin secretion in Wistar and GK rats

目的观察高脂饮食对正常血糖Wistar大鼠和高血糖GK大鼠糖脂代谢及胰岛素分泌功能的影响。方法雄性Wistar和GK大鼠各20只,随机分为4组(n=10):Wistar普食组(WND),Wistar高脂组(WHD),GK普食组(GND)和GK高脂组(GHD)。分别以普通饲料和高脂饲料喂养12周,测定大鼠的糖脂代谢指标,并采用口服葡萄糖胰岛素释放试验评估胰岛素分泌能力。结果实验12周后,WHD和GHD组的内脏脂肪占体质量百分比分别显著高于WND和GND组,(8.20±0.50)%vs(6.00±0.60)%和(8.40±0.70)%vs(6.80±0.90)%(P均<0.01)。GHD组的空腹血糖(FPG)明显高于GND组,(12.85±1.44)vs(9.71±0.42)mmol/L(P<0.01);而WHD和WND组的FPG无显著差异。WHD和GHD组的胰岛素曲线下面积/葡萄糖曲线下面积分别显著小于WND和GND组,8.61±1.17vs11.26±1.37和0.95±0.11vs1.23±0.17(P均<0.01)。结论正常血糖和高血糖状态下,高脂饮食均可引起Wistar和GK大鼠中心型积聚的体脂增加,导致葡萄糖耐量和胰岛素分泌能力减退,为2型糖尿病进程中的重要危险因素。

Objective To observe the effects of high-fat diet on carbohydrate, lipid metabolism and insulin secretion in euglycemic Wistar rats and hyperglycemic GK rats. Methods Twenty male Wistar and twenty matched GK rats were randomly divided into 4 groups： Wistar control group （WND, n =10） , Wistar high-fat-diet group （WHD, n =10） , GK control group （GND, n =10） and GK high-fat-diet group （GHD, n = 10）. High-fat-food or normal food were administered to each group for 12 consecutive weeks. The parameters of carbohydrate and lipid metabolism were measured, and insulin secretion ability was estimated by oral glucose tolerance test and insulin release test among the four groups. Results After 12 weeks＇ experiment, the percent of visceral fat weight to body weight in WHD and GHD group was significantly higher than that in WND and GND group, respectively, （8.20 ± 0.50） % vs （6.00 ± 0.60 ） % and （8.40 ± 0.70） % vs （6.80 ± 0.90） % , respectively （ P 〈 0.01 for both ）. Fasting plasma glucose （FPG） of GHD group was significantly higher than that of GND group, （ 12.85 ± 1.44） vs （9.71 ±0.42） mmol/L（P 〈0.01 ） , while there was no significant difference between WHD and WND group. The area under the curve of insulin / area under the curve of glucose in,WHD and GHD groups was significantly lower than that in WND and GND group, respectively, 8.61 ±1. 17 vs 11.26 ±1.37 and 0.95 ±0.11 vs 1.23 ±0.17 （P 〈0.01 for both）. Conclusion Under normal or high-glucose conditions, high-fat diet can lead to fat accumulation in abdomen, impaired glucose tolerance and impaired insulin secretion ability, which may be an important risk factor in the progression of type 2 diabetes.