早期营养干预对宫内生长迟缓大鼠瘦素、胰岛素敏感性的影响

目的　探寻既能保证宫内生长迟缓 (IUGR )大鼠生长追赶又可避免或减轻其在成年期产生胰岛素抵抗 (IR)的早期营养干预措施。方法　用孕鼠全程饥饿法建立IUGR大鼠模型。IUGR新生雌鼠60只随机分为五组 :( 1)IUGR对照组给予常规饲料 ;( 2 )高碳水化合物组 ;( 3 )高脂肪组 ;( 4 )高蛋白质组 ;( 5 )低蛋白质组。正常新生雌鼠 12只为正常对照组。幼鼠在 3周喂乳期间母鼠分别摄食上述饲料 ,第 4周起各组幼鼠均以常规饲料饲养。各组新生鼠于第 4周、12周分别测定体重、肾周脂肪重量、血清瘦素、血糖、胰岛素并计算胰岛素敏感指数 (ISI)。结果　IUGR高蛋白质组在 4周呈现不伴肾周脂肪增加的体重追赶生长 ,在 12周肾周脂肪不增多 ,瘦素、ISI均与正常对照组比较差异无显著性 ,不出现IR。结论　生后哺乳期高蛋白饮食继后恢复正常饮食是早期营养干预IUGR的合理措施。 12周时血清瘦素水平可作为观察IUGR大鼠成年后发生IR的一个生化指标。

Improvement of leptin and insulin sensitivity due to early nutritional intervention in rats born with intrauterine growth retardation

Objective To look for an appropriate dietary pattern of early nutritional intervention, which does not only meet the need of catch-up growth but also avoids or reduces the incidence of insulin resistance (IR) in adulthood of rats born with intrauterine growth retardation (IUGR). Methods The model of IUGR in rats was established by maternal nutrition restriction. Sixty newborn female rats with IUGR were randomly divided into 5 groups: (1) IUGR control group fed with common diet. (2) IUGR high-carbohydrate diet group. (3) IUGR high-fat diet group. (4) IUGR high-protein diet group. (5) IUGR low-protein diet group. The IUGR newborn rats were breast-fed for 3 weeks, while the mother rats were fed with the above different diets with the same caloric amount. Twelve normal newborn female rats served as a normal control group and were fed with common diet. All newborn rats were fed routine diet starting from the 4th week of experiment. The body weight, perirenal fat weight and the serum leptin, blood glucose, insulin concentration were measured and the insulin sensitive index (ISI) were calculated at the 4th week and the 12th week of life. Results The IUGR rats fed with high-protein diet showed a catch-up growth without the increase of perirenal fat at the 4th week, a normal level of perirenal fat, leptin and ISI at the 12th week compared with the normal control group, and did not show IR. The groups fed with high carbohydrate diet and high fat diet also showed a catch-up growth, but did the same as the IUGR control group in other aspects, they all showed increased perirenal fat, higher levels of leptin, lower ISI and IR at adulthood. The group fed with low protein diet did not show IR, but kept a small body size with increased perirenal fats. The serum leptin level of rats was positively correlated to body weight at the 4th week of life and was positively correlated to the weight of perirenal fat and negatively correlated to ISI at the 12th week of life. Conclusion High protein diet is an appropriate early nutritional intervention for rats with IUGR. The serum leptin level at the 12th week of life seems to be an index of IR in adult rats with IUGR.