孕前和孕期高脂饮食对新生仔鼠体格生长及胰岛素样生长因子-1的影响

Effect of high-fat diet before and during pregnancy on growth and serum insulin-like growth factor-1 level in neonate rats

目的 利用高脂饮食建立动物模型,观察孕前和孕期高脂饮食对新生仔鼠体格生长及胰岛素样生长因子1（IGF-1）的影响.方法 40只雌性SD大鼠采用简单随机抽样方法分为高脂组和对照组,分别喂养35％高脂饲料和普通饲料.喂养8周后,高脂组和对照组各取8只观察母鼠肝脏组织病理;其余与普通饲料喂养的雄性大鼠交配,孕期分别继续给予高脂饲料或普通饲料喂养.新生仔鼠出生24 h内检测各项指标：测量出生体质量和体长（鼻尾长度）;酶联免疫吸附试验测定其血清IGF-1水平;生化分析仪检测血生化指标;光镜下观察肝脏组织病理;Western blot检测肝脏IGF-1蛋白的表达.结果 1.高脂组仔鼠的出生体质量和体长均较对照组显著降低（P均＜0.05）.2.高脂组仔鼠血清IGF-1水平较对照组下降20.1％,但差异无统计学意义（P＞0.05）.3.高脂组仔鼠的天冬氨酸转氨酶（AST）显著高于对照组（P＜0.05）,其余各项血生化指标差异无统计学意义（P均＞0.05）.4.高脂组母鼠及仔鼠肝组织可见脂肪变,而对照组肝脏病理形态正常.5.高脂组仔鼠肝脏IGF-1蛋白的表达高于对照组（P＜0.05）.结论 母亲孕前和孕期高脂饮食会影响胎鼠在宫内的体格生长,可能与IGF-1的下降有关,但导致血清IGF-1下降的病因以及宫内体格生长迟缓的确切病理机制尚有待进一步阐明.

Objective To establish neonate rate models induced by high-fat diet so as to explore the effect of high-fat diet before and during pregnancy on growth and serum insulin-like growth factor-1 （IGF-1） level in neonate offspring.Methods Forty female SD rats were divided into high-fat group and control group that were fed with 35% high-fat diet and standard chow,respectively.After 8 weeks,8 rats from each group were euthanatized for liver pathology and the other female rats were mated with male rats and fed continuously with 35% high-fat diet and standard chow throughout gestation,respectively.Offspring from both groups were studied within 24 hours after birth.Their birth weight and body length （from apex nasi to end of tail） were measured.Enzyme-linked immunosorbent assay was used to detect serum IGF-1 level.Serum biochemical indexes were tested by biochemical analyzer.Liver pathologic changes were observed under the light microscope.The expression of IGF-1 in liver samples was detected by Western blot.Results 1.Rats in the high-fat group showed a significant less birth weight and shorter body length compared with those in the control group（all P 〈 0.05）.2.The level of serum IGF-1 of offspring in the high-fat group decreased by 20.1% in comparison to offspring in the control group,but there was no significant difference between the 2 groups （P 〉 0.05） because of the limited sample sizes.3.The aspartate transaminase（AST） of offspring in the high-fat group increased compared with those from control group（P 〈 0.05）,while other serum biochemical indexes between the 2 groups showed no significant differences（all P 〉0.05）.4.Fatty degeneration could be found in livers of both dams and offspring in the high-fat group under light microscope,while the samples of both dams and offspring from the control group all showed normal.5.The IGF-1 expression in livers of offspring from high-fat group increased in comparison to that from control group（P 〈 0.05）.Conclusions A maternal high-fat diet before and during pregnancy decreases the birth weight and body length of offspring in utero,which may be associated with the decreased IGF-1.However,the pathogenesis of decreased IGF-1 in this study can not been found.Further study is needed to clarify the mechanism of intrauterine growth retardation induced by high-fat diet.