宫内发育迟缓雌性仔鼠早期营养对生长追赶的影响

Effects of Early Life Nutritional Status on Weight Catch-up Growth,Puberty Initiation and Obesity in Female Rats with Intrauterine Growth Retardation

【目的】探讨生命早期不同营养状态对宫内发育迟缓(IUGR)雌性大鼠体质量生长追赶、青春发育启动及肥胖的影响。【方法】SPF母鼠孕期限制饮食法建立仔鼠IUGR模型,采用雌性仔鼠进行实验,IUGR仔鼠哺乳期以小窝喂养(SL-IUGR)模拟过度喂养,同时设IUGR仔鼠常规哺乳(CF-IUGR),正常对照组仔鼠常规哺乳(NC),3组仔鼠均在21d断乳后以基础饲料喂养,分别于仔鼠生后1、7、14、21、35、42和75d称体质量,记录阴门开启时间,21、35d采血检测雌二醇(E2)、黄体生成素(LH)、卵泡雌激素(FSH)水平进行比较。【结果】IUGR组仔鼠出生体质量(4.9±0.2)g,低于对照组(6.0±0.3)g,差异有统计学意义(P<0.001)。IUGR大鼠生后14d均出现生长追赶,SL-IUGR组大鼠14~75d体质量均高于对照组,CF-IUGR组大鼠1~75d体质量均落后于对照组,差异有统计学意义(P<0.05)。SL-IUGR组雌性大鼠的阴门开启时间(29.88±1.81)d,较CF-IUGR组(32.03±2.11)d提前,差异有统计学意义(P=0.044);21d体质量与IUGR大鼠阴门开启时间具有相关性,Rs=-0.174,P=0.039。SL-IUGR组大鼠青春期、成年期肥胖率为28.33%、21.67%,较CF-IUGR组7.5%、6.25%增加,差异有统计学意义(P=0.001、0.007)。青春期肥胖IUGR大鼠7d、21d体质量生长速度较不发生青春期肥胖者增加,成年期肥胖IUGR大鼠7d、35d体质量生长速度较不发生青春期肥胖者增加,差异有统计学意义(P<0.05)。IUGR组大鼠阴门开启时间和成年期肥胖二元Logistic回归分析OR=0.419,P=0.24,阴门开启时间不是成年期肥胖的独立因素。【结论】生命早期营养水平提高有利于IUGR体质量追赶;哺乳期体质量过度追赶可导致IUGR大鼠青春期肥胖及成年期肥胖和阴门开启时间提前。

【Objective】To investigate the effects of different nutritional status in early life on weight catch-up,puberty initiation and obesity in rats with intrauterine growth retardation(IUGR).【Methods】IUGR model of newborn rats was established by limiting diet during pregnancy in SPF rats.Female newborn rats were used in the experiment.IUGR rats were divided into two groups:small litter IUGR group(SL-IUGR)and common feeding IUGR group(CF-IUGR).Rats of normal birth weight served as normal control group(NC).The SL-IUGR group was used to simulate overfeeding in lactation period.After weaning,the rats in the three groups were fed with basic diet.The weights were measured at postnatal 1,7, 14,21,35,42 and 75 days.The time of vaginal orifice opening(VO)was recorded.The levels of estradiol(E2),luteinizing hormone(LH)and follicle estrogen(FSH)were examined on the 21 d and the 35 d.【Results】The birth weight of IUGR rats was(4.92±0.18)g,which was significantly lower than that in the control group(6.00±0.29 g,P < 0.001). IUGR rats showed weight growth catch-up on the 14th day.The body weight of SL-IUGR group was higher than that of control group from 14 to 75 d.The body weight of CF-IUGR group lagged behind that of control group from 1 to 75 d,the difference was statistically significant(P < 0.05).The vaginal opening time of female IUGR rats in SL-IUGR group was (29.88 ±1.81)d,which was significantly earlier than that of CF-IUGR group(32.03±2.11)days(P = 0.044).There was a correlation between body weight of the 21 d and vaginal opening time in IUGR rats,Rs =-0.174,P = 0.039.The obesity rates of puberty and adulthood of IUGR rats in SL-IUGR group were 28.33% and 21.67%,which were significantly higher than those in CF-IUGR group(7.5%,6.25%;P = 0.001,0.007).The weight growth rate of adolescent obese IUGR rats at 7 and 21 d was higher than that of non-adolescent obese rats,and the weight growth rate of adult obese IUGR rats at 7 and 35 d was higher than that of non-adolescent obese rats.The difference was statistically significant(P < 0.05).Binary Logistic regression analysis of vaginal opening time and adult obesity in IUGR rats′ group OR = 0.419,P = 0.24.The time of vaginal orifice opening was not an independent factor of adult obesity.【Conclusions】The improvement of nutrition level in the early stage of life is beneficial to weight catch-up of IUGR,and the overweight catch-up during lactation can lead to puberty and adulthood obesity of IUGR rats,as well as the advance of vaginal opening time.