不同能量及营养结构饮食对雌性大鼠性发育的影响

Effects of diets with different calorie and nutritional values on sexual development in female rats

目的观察不同能量和不同营养结构饮食对雌性大鼠青春期启动的影响。方法分别用不同能量（实验一：限制能量与正常能量）和不同营养结构（实验二：高脂、高糖、高蛋白与正常）饲料喂养大鼠，观察大鼠体重、进食量、阴道开口日龄，予阴道开口日处死大鼠，称重子宫、卵巢、双肾周脂肪组织，测定血清瘦素、胃促生长素（ghrelin）、胰岛素样生长因子Ⅰ（IGF—Ⅰ）浓度。结果阴道开口日龄限制组比对照组明显延迟（P〈0．01）；限制组阴道开口时体重、子宫重量、子宫指数、每日热卡摄入量、瘦素、ghrelin水平均显著低于对照组（P〈0．01），IGF—Ⅰ水平无差异。高脂组、高糖组、高蛋白组的阴道开口日龄均比对照组明显延迟（P〈0．01）；高脂组、高糖组发育时体重、双肾周脂肪重量高于高蛋白组和对照组；每日热卡摄入量高糖组最高，高蛋白组最低；血清瘦素水平高脂组最高，高蛋白组最低；ghrelin水平高糖组最高，高蛋白组最低；IGF—Ⅰ水平、子宫指数组间比较均无显著性差异。结论雌性大鼠正常青春期的启动需要提供足够的能量和结构均衡的饮食，低能量、高脂肪、高糖、高蛋白的饮食均会延迟雌性大鼠青春期的启动。

Objective Tn investigate the effects of diets with different caloric and nutritional values on pubertal onset in female rats. Method Female Wistar rat models receiving calorie-deprived （group R） （ Experiment 1 ）, fat-rich （ group F）, glucose-rich （ group G） and protein-rich （ group P） （ Experiment 2 ） test diets were established, and rats receiving diets with normal caloric value were considered as control group （group C）. The body weight （BW） ,food-intake and vaginal patency （VP） were observed. The rats were killed at the day of vaginal patency. The BW, uterus weight （ UW ）, uterus index （ UI ）, calorie intake per day （ CI ）, perirenal fat weight （PFW） and perirenal fat index （PFI） were measured. The serum levels of leptin, ghrelin, IGF- Ⅰ were tested by means of ELISA. Results Experiment 1 ： The VP was retarded in group R compared with group C （ P〈 0. 01 ）. There was a significant difference in BW,UW, UI,CI,leptin and ghrelin at the VP day between group R and group C （all P〈 0.01 ） ,and no significant difference in IGF- 1 levels between these two groups. Experiment 2 ：The VP was retarded in group F,group G and group P in comparison with group C （P〈0. 01 ）. The BW, PFW and PFI in group G and group F were markedly higher than those in group P and group C. The leptin level in group F was the highest,and the lowest in group P. The ghrelin level in group G was the highest,and that in group P was the lowest. However, there were no significant differences in IGF- Ⅰ and UI among these four groups. Conclusion The normal pubertal onset of female rats requires sufficient caloric stores and balanced nutrient. Diets malnutrition and fat-rich, glucose- rich and protein-rich test diets all delay pubertal onset in female rats.