哺乳期过度喂养致幼鼠肥胖及动脉粥样病变

目的探讨SD大鼠哺乳期过度喂养乳汁与幼年大鼠肥胖及动脉粥样病变的关系。方法将出生第3天的雄性SD新生大鼠随机分为对照组和模型组,模型组3只一笼,过度喂养组10只一笼,每笼分别由其母孕鼠喂养至21天,断乳后两组大鼠均正常食料喂养60天,观察两组大鼠体重、身长,计算Lee’s指数;测定附睾及肾周脂肪重量,计算体脂比;测定两组大鼠血糖、血脂、胰岛素,计算胰岛素敏感指数。HE染色观察腹主动脉组织病理改变。结果出生21天时,过度喂养组较对照组体重、脂体比、Lee’s指数明显增加(P<0.05,t值分别为-13.93,-2.73,-4.87),血胰岛素分泌和胰岛素敏感指数均较对照组高(P<0.01,t值分别为-10.217,12.027),血糖无明显差异(t=-2.08,P>0.05)。出生后60天,过度喂养组较对照组体重、脂体比、Lee’s指数明显增加(P<0.01,t值分别为-10.55,-3.93,-5.99),血胰岛素分泌和胰岛素敏感指数、血糖和血三酰甘油均明显升高(P<0.05,t值分别为-2.26,-9.028,9.734,-5.472)。生后60天过度喂养组大鼠腹主动脉内膜明显增厚伴纤维化,内膜与中膜间可见粥样斑块、泡沫细胞及散在钙化灶,中膜平滑肌细胞增多、排列紊乱、核深染,其长轴垂直于弹力纤维,血管壁向管腔内突出。结论哺乳期过度喂养乳汁可致乳鼠肥胖,终止过度喂养后大鼠肥胖仍可持续至青春期并出现代谢综合征及动脉粥样病变。

Over-feeding During Lactation Induced the Obesity and Atherosclerosis of Rats in Adolescence.

Objective To investigate the effect of over-feeding during lactation on obesity and atherosclerosis of SD male rats in adolescence.Methods At postnatal 3 days,male rats were randomly distributed among the mothers.The litter size was adjusted to10 newborns to induce normo-feeding(control) or to three rats to induce overfeeding(model).At postnatal 21 days,they were weaned and normal fed.60 days later,a group of 6 were randomly to beselected to observed body weight,length,epididymal and perirenal fat weight,Lee′s index,while animals in each group were measured for blood glucose,blood lipids,insulin and calculate insulin sensitivity index.HE stain we observed the pathological changes of the abdominal aorta.Results The body weight,body fat ratio,Lee ′s index,insulin secretion and insulin sensitivity index in over-feeding group were significantly higher than the control group(P<0.05) at postnatal 21 days.However,the level of blood glucose showed no significant differences between the two groups(P>0.05).At 60 days after birth,there was statistically significant increase in body weight,body fat ratio,Lee ′s index,blood glucose,blood lipids,blood insulin and insulin sensitivity index of over-feeding group than contronl group(P<0.05).At postnatal 60 days,the intima of the abdominal aortic in over-feeding groups rats was obviously thickened with fibrosis.The atheromatous plaque,foam cells and scattered calcification were seen at intimal-medial membrane of abdominal aortic and the smooth muscle cells of the vessels were increased and disordered in over-feeding groups.Meanwhile,the smooth muscle cells nuclei were depth dye and the cell′s long axis was perpendicular to the elastic fibers.The vessel wall was convex to the lumen.Conclusion Over-feeding during lactation can cause obesity of rats,and the obesity can still be continued to adolescence after termination of over-feeding and induced the metabolic syndrome and atherosclerosis.