Effects of Early Life Nutritional Status on Weight Catch-up Growth，Puberty Initiation and Obesity in Female Rats with Intrauterine Growth Retardation / 中山大学学报(医学科学版)

ABSTRACT

@#【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 besity 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.