限食后追赶生长对大鼠胰岛素抵抗的影响

EFFECTS OF CATCH-UP GROWTH AFTER SEMISTARVATION ON INSULIN RESISTANCE IN RATS

目的:研究营养供给的剧烈波动对大鼠生长发育和胰岛素抵抗的影响。方法:6w龄Wistar大鼠随机分为5组,对照组(NC)给开放普通饮食(脂肪热卡比18.94%),高脂组(HF)给予开放高脂饮食(脂肪热卡比50.55%),限食组(FR)给半量普通饮食喂养4w,限食后开放普通饮食组(RN)在限食4w结束后继续给自由开放普通饮食8w,限食后开放高脂饮食组(RH)限食结束后给自由高脂饮食8w。除FR组以外,所有实验动物均喂养12w,在造模过程中检测动物的进食量、体重变化,造模结束后检测动物胰岛素抵抗指数(HOMAIR)、内脏脂肪重量/体重比值和血清生化指标变化。结果:82.25%的实验动物在限食后开放饮食过程中出现追赶生长。出现追赶生长的实验动物在实验结束时,体重并未能完全追赶上NC组。RH组内脏脂肪(以附睾和肾周脂肪代表)/体重比值和甘油三酯(TG)明显高于NC组,与HF组接近;RN组这2个指标与NC组接近。2组追赶生长组HOMAIR都高于对照组和HF组。追赶生长对空腹血糖影响不大。结论:追赶生长会导致实验动物胰岛素抵抗,但该抵抗与动物的肥胖、高TG血症程度并不完全一致。

Objective： To study the effect of catch up growth after semistarvation on insulin resistance in rats. Methods： Wistar rats （n=40） were randomly divided into 5 groups： normal chow group （NC given diet with 18.94% of calories as fat for 12 w）; high fat group （HF, given diet with 50.55% of calories as fat for 12 w）; food restriction group （FR, 50% of their normal spontaneous food for 4 w）; refeeding normal chow group （RN, after 4 w semistarvation, given normal diet for another 8 w ）; refeeding high fat diet group （RH, after 4 w semistavation, given high fat diet for 8 w）. Changes of body weight, height, and food intake were recorded. At the end of experiment, homeostasis model assessment of insulin resistance （HOMAIR）, the rate of abdominal fat （including perirenal fat and epididymal fat） vs weight, plasm protein, blood lipid （including total cholesterol and triglyceride） were detected. Results： There were 82.5% rats getting catch-up growth in refeeding groups. Body weight of both refeeding groups could not catch that of NC group, but the rate of visceral fat vs weight was higher than that of NC group, and this rate of RH group was close to that of HF group. The changes of visceral fat vs body weight were consistent with that of TG levels. All nutritional status except high fat diet could not influence total cholesterol levels. RH and RN group’s HOMAIR were higher than those of NC group and HF group. All groups have similar fastingglucose levels. Conclusion： Catch-up growth can induce insulin resistance, but is not consistent with fat accumulation and hypertriglyceridemia in rats.