早期不同饮食营养干预对宫内生长迟缓幼鼠生长追赶的影响

目的　探讨生后早期给予不同饮食构成的营养干预对宫内生长迟缓 (IUGR)幼鼠生长追赶的影响。方法　采用孕母饥饿法建立IUGR大鼠模型 ,32只IUGR新生雌鼠和 8只正常新生雌鼠随机分为五组 (每组 8只 ) :①正常对照组 (C组 ) ,②IUGR模型组 (S组 ) ,③IUGR低蛋白组 (SL组 ) ,④IUGR高蛋白组 (SH组 ) ,⑤IUGR高热卡组 (SA组 )。于生后第 4周测定各组幼鼠的血清胰岛素样生长因子 1(IGF1)及其结合蛋白 3(IGFBP3)浓度和体重、身高、小肠重量、长度及小肠绒毛高度 (VH)、隐窝深度 (CD)、吸收表面积 (VSA)、粘膜厚度 (MT)。结果　IUGR高蛋白组血清IGF1、IGFBP3和小肠VH、VSA、MT及体重均高于C组和S组 (P <0 0 5或P <0 0 1) ;小肠重量、长度和身高与C组比较差异无显著意义 (P >0 0 5 )。血清IGF1与IGFBP3、小肠重量、长度和VH、VSA及体重、身高均呈正相关 (均P <0 0 5 )。结论　血清IGF1是反映生长追赶和营养状态的灵敏指标 ,与小肠和体格的生长追赶呈正相关。生后早期予高蛋白饮食组干预效果较佳 ,可通过促进小肠绒毛的发育和增加营养物质吸收表面积而达到满意的生长追赶。

Effect of different early nutritional interventions on catch-up growth of rats with intrauterine growth retardation

OBJECTIVE: About 20 - 50% individuals with intrauterine growth retardation (IUGR) could not achieve catch-up growth and remain small in size till adulthood. There are few reports on the relation between intestinal development and body catch-up growth of IUGR. Studies showed that early "nutritional programming" would results in long-term effects on the body growth and organic function, and gastrointestinal development is closely related to the body development as well. The authors aimed to study the effect of early nutritional interventions on serum IGF1, IGFBP3, intestinal development and catch-up growth of pups with IUGR by using diets with different protein and caloric levels during the first four weeks of life. METHODS: An IUGR rat model was established by maternal nutrition restriction during pregnancy. Thirty-two IUGR female pups were divided randomly into 4 groups (8 pups in each group) and eight normal female pups as control. The groups and interventions were (1) Normal control group (C group); (2) IUGR control group (S group), (3) IUGR low-protein diet group (SL group); (4) IUGR high-protein diet group (SH group); (5) IUGR high-caloric group (SA group). The serum IGF1, IGFBP3, body weight, body length, and intestinal weight, length, intestinal villi height (VH), crypt depth (CD), villi absorbing area (VSA), mucous thickness (MT) were measured at the 4(th) week of life. RESULTS: (1) At the 4(th) week, the serum IGF1 (724.0 +/- 153.5 ng/ml), IGFBP3 (9.69 +/- 3.13 ng/ml), and VH (416.9 +/- 46.3 microm), VSA (115.9 +/- 24.0 x 10(3) microm(2)), MT (583.9 +/- 68.5 microm) in the SH group were significantly higher than those of normal control group (539.4 +/- 198.4 ng/ml, 4.77 +/- 2.98 ng/ml and 322.1 +/- 25.8 microm, 85.8 +/- 17.8 x 10(3) microm(2), 480.0 +/- 61.5 microm) and IUGR control group (P < 0.05). The intestinal weight (1.91 +/- 0.16 g) and length (80.67 +/- 9.47 cm) in the SH group was not significantly different from the normal control group (2.24 +/- 0.22 g and 74.77 +/- 9.06 cm, P > 0.05). The SH group showed the fastest catch-up growth. Their body weights (40.14 +/- 11.03 g) at the 3(rd) week and body lengths (23.61 +/- 0.49 cm) at the 4(th) week of life reached the normal ranges of the control group (44.65 +/- 5.36 g and 23.10 +/- 1.42 cm, P > 0.05). (2) The serum IGF1 (346.7 +/- 85.3 ng/ml), IGFBP3 (1.4 +/- 0.21 ng/ml), body weight (21.41 +/- 3.54 g) and body length (15.96 +/- 1.29 cm) and the most of intestinal indexes in the SL group were markedly lower than other groups at the 4(th) week of life (P < 0.05). CONCLUSION: The serum IGF1 was a sensitive marker to reflect the catch-up growth and nutritional status, and IGF1 was positively correlated with the intestinal development and body growth. When given different nutritional interventions during the first four weeks of life, high protein diet is more helpful for the IUGR catch-up growth by promoting the intestinal development and the absorption of nutrition.