Objective: To study the efficacy of metformin intervention on insulin resistance during catch-up growth in mice with fetal growth restriction (FGR).
Methods: Mouse models of FGR were established by low protein diet feeding of the pregnant mice. Both the newborn female mice with FGR and normal control (NC) mice were randomized for feeding with a standard diet (SF) or a high-fat diet (HF) after weaning and treatment with gavage of either metformin or normal saline. The mice were examined for vaginal opening time and the estrous cycle at the age of 8 weeks. At the age of 12 weeks, 6 mice in anestrus from each group were fasted for 12 h for measurement of body weight, height, poundera index (PI), fasting blood glucose (FBG), fasting insulin (Fins), follicle stimulating hormone (FSH) and anti-Mullerian hormone (AMH), and the HOMA-IR was calculated. The reproductive capacity of female mice was assessed by mixing them with male mice at the ratio of 2:1. The 3 × 2 factorial analysis was conducted to determine the interactions between FGR, high-fat feeding and metformin.
Results: Factorial analysis showed that FGR and high-fat feeding had significant effects on the PI index, Fins, HOMA-IR, vaginal opening time, and AMH (P<0.05). Metformin significantly affected the factors related to high-fat feeding including weight, PI, FPG, Fins, HOMA-IR and estrous cycle (P<0.05) and the factors related to FGR with the exception of height and FSH (P<0.05). FGR significantly affected the factors tested except for body weight (P<0.05); high-fat feeding affected all the factors but the FSH (P<0.05); metformin affected all the factors but the height and FSH (P<0.05). In the female mice treated with saline, the pregnancy rates differed significantly between FGR mice with high-fat feeding and control mice with standard feeding, and between FGR mice with standard feeding and high-fat feeding (P<0.05).
Conclusion: FGR mice can present with delayed puberty with rare ovulation and adulthood insulin resistance, and high-fat feeding after birth can promote the catch-up growth of FGR mice. Metformin intervention is effective for improving insulin resistance and reproductive-endocrine disorders in FGR mice during catch-up growth.
目的: 探讨二甲双胍干预胎儿生长受限（FGR）小鼠追赶生长时期胰岛素抵抗的有效性。
方法: 采用孕期低蛋白饮食法建立FGR小鼠模型。FGR组和正常对照组（NC）新生雌鼠自断乳后分别喂予标准饲料（SF）和高脂饲料（HF）, 不同饲料喂养组又分为二甲双胍灌胃组（MF）和生理盐水灌胃组（NS）, 即：NC+SF+NS组、NC+SF+MF组、NC+HF+NS组、NC+HF+MF组、FGR+SF+NS组、FGR+SF+MF组、FGR+HF+NS组、FGR+HF+MF组。于仔鼠8周龄开始每组取6只观察阴道开口时间及动情周期变化。第12周在动情间期每组取6只小鼠禁食12 h, 测体质量、身长, 计算体质量系数（PI）, 采血取血清进行空腹血糖（FPG）、空腹胰岛素（Fins）、促卵泡生成素（FSH）、抗苗勒管激素（AMH）检测, 并计算胰岛素抵抗指数（HOMA-IR）。第12周始每组取6只小鼠, 与雄鼠2:1合笼交配, 了解雌鼠生殖能力。组间比较采用单因素方差分析, 组间差异采用Fisher精确概率检验, 以FGR、HF及MF三个因素为分析指标, 采用3×2析因实验分析, 确定有无交互作用, 以及交互作用的显著性水平。
结果: （1）析因分析：FGR因素及HF因素对PI指数、Fins、HOMA-IR、阴道开口时间、AMH均有交互相加作用的显著性影响（P＜0.05）；MF因素干预HF因素相关的体质量、PI指数、FPG、Fins、HOMA-IR及动情周期开始时间有显著性意义（P＜0.05）；除身长、FSH外, MF因素干预FGR因素相关的其余观察指标均有显著性意义（P＜0.05）。（2）组间比较：除体质量外, FGR因素对其余观察指标的影响差异均有统计学意义（均P＜0.05）；除FSH外, HF因素对其余观察指标的影响差异均有统计学意义（均P＜0.05）；除身长、FSH外, MF因素对其余观察指标的影响差异均有统计学意义（均P＜0.05）；另FGR+HF+NS组与NC+SF+NS组、FGR+SF+NS组与FGR +HF+NS组妊娠率的差异有统计学意义（P＜0.05）。
结论: FGR小鼠存在青春期延迟、稀发排卵及成年期胰岛素抵抗, 出生后高脂饮食促发FGR小鼠的追赶生长, 追赶生长时期的二甲双胍干预对其胰岛素抵抗、生殖内分泌紊乱的改善具有有效性