目的：生后早期的生长主要受营养的调控，营养物质-胰岛素-胰岛素样生长因子(IGF)轴在胎儿宫内发育迟缓(IUGR)生长追赶及胃肠发育中起着重要的作用，而胃肠发育又与营养物质的吸收、生长追赶关系密切。目前国内有关IUGR出生时小肠发育状况报道甚少，且仅限于IUGR出生时胃肠形态结构的观察。该研究探讨生后早期不同蛋白质和热卡水平的营养干预如何调控IGF系统及影响IUGR大鼠的小肠发育和体格生长追赶，并追踪至成年期。方法：采用孕母饥饿法建立IUGR模型。64只IUGR新生鼠随机分为4组：IUGR正常饮食组(SC组)，饮食中蛋白含量20%；IUGR高蛋白组(SH组)，饮食中蛋白含量占30%；IUGR低蛋白组(SL组)，饮食中蛋白含量为10%；IUGR高热卡组(SA组)，饮食中热卡较其它组高20%。16只正常新生鼠为正常对照组(C组)予以正常饮食。幼鼠3周断乳后继续予原饮食模式1周，第4周起各组均予正常饮食喂养。分别于出生时及生后第4周、12周测定各组大鼠的血清IGF-1、胰岛素生长因子结合蛋白-3(IGFBP-3)浓度及体重、身长和小肠重量、长度。结果：IUGR大鼠虽然宫内营养不良，但SH组及SA组呈快速小肠发育和体格生长追赶伴IGFs水平明显升高，其中4周时SH组IGFs水平显著高于其余各组(P<0.05)；SC组也呈相对较慢的小肠发育和体格生长追赶，IGFs无明显升高(P>0.05)。SL组4周和8周的体重、身长、小肠长度和重量均低于其它4组(P<0.05)，4周时IGFs水平低于其它各组(P<0.05)。4周时IGF1与生长追赶及小肠发育呈正相关(均P<0.05)，12周时无显著相关(P>0.05)。结论：4周时血清IGF-1是反映生长追赶的灵敏指标，与小肠和体格的生长追赶呈正相关，至成年期这种相关性消失。

OBJECTIVE: Nutrition insulin like growth factors (IGFs) axis is important to body catch up growth and gastrointestinal development, while gastrointestinal development is closely related to the nutritional absorb and catch up growth in infants with intrauterine growth retardation (IUGR). Now there are few reports about the postnatal intestinal development of IUGR infants in our country, and the reports have mainly focused on the gastrointestinal morphology and structure of new born IUGR rats. This research aims to study the effects of early postnatal diet with different levels of protein and caloric on serum IGF 1, IGFBP3, intestinal development and catch up growth in rats with IUGR. METHODS: The IUGR rat model was established by nutrition restriction. Sixty four IUGR pups were randomly assigned into four groups: the IUGR model group, the IUGR high protein diet group, the IUGR low protein diet group and the IUGR high caloric group. The rats in the four groups were fed with a normal protein, a 30% protein and a 10% protein diets, and a diet with caloric being higher by 20% than the other three groups respectively. Sixteen normal pups receiving normal diet were served as the control group. The serum concentrations of IGF 1 and IGFBP3, body weight, body length and intestinal weight and length were measured at the 4th and 12th weeks after birth respectively. RESULTS: The IUGR high protein diet and high caloric diet groups manifested quick intestinal development and catch up growth, as well as the increased IGFs level; the IGFs level of the IUGR high protein diet group at the 4th week after birth was significantly higher than the other groups (P< 0.05 ). The IUGR model group manifested a relatively slow intestinal development and catch up growth and a non increased IGFs level. The body weight, body length and intestinal weight and length in the IUGR low protein diet group at the 4th and 8th weeks after birth were lower than those of other groups and the IGFs level was lower at the 4th after birth compared with that of the other groups (P< 0.05 ). The IGFs level was positively correlated to body weight, body length and intestinal weight and length at the 4th after birth (r= 0.930 , 0.884 , 0.678 , 0.978 respectively, all P< 0.05 ). At the 12th week after birth, there was no correlation among them. CONCLUSIONS: IGF 1 is a sensitive index reflecting catch up growth and is positively related to intestinal development and body catch up growth during childhood (4th week of life), while the correlation disappears at adulthood (12th week of life).