Comparison of rat models of intrauterine growth retardation established by three different methods / 中国比较医学杂志

ABSTRACT

Objective Intrauterine growth retardation (IUGR) is characterized by low birth weight of neonates. The aim of this study was to provide a reference for the establishment of IUGR models in scientific research, by comparing the experimental data of different rat models of IUGR established by three commonly-used methods. Methods A total of 20 pregnant rats on the day 0 of gestation were divided into 4 groups, with 5 rats in each group (n=5). Among them, 3 groups of rats were treated with alcohol intervention (group A), uterine artery ligation (group U), and low protein diet (LP group), respectively, to establish rat models of IUGR, and the fourth group served as the normal control group (CON group). Fetal rats were taken through cesarean section on the 20th day of gestation. The body mass, brain mass, placental mass, two-kidney mass, body length and tail length of the fetal rats were measured, and the incidence rate of IUGR, stillbirth rate and their brain to placenta ratio were calculated. The fetal rats in each group were continuously raised and the body mass, perirenal fat pad mass and some organ masses were determined at the 3rd, 6th and 12th weeks. Results The average body mass of the fetal rats in the groups A, U and LP group was significantly lower than that of the normal control group (P＜ 0. 05), and the incidence rate of IUGR of the fetal rats was significantly higher than that of the normal control group (P＜ 0. 05). In addition, the stillbirth rate of pregnant rats in the group U was significantly higher than those of the group A and LP group (P ＜ 0. 05). After raising the rats for 3 weeks, the average body mass of rats in the three experimental groups was significantly lower than that of the normal control group (P ＜ 0. 05), and after raising for 6 weeks, the average body mass in the three experimental groups was still lower than that of the normal control group, but with a non-significant difference (P＞ 0. 05). However, after raising for 12 weeks, the average body mass of the rats in the group A and LP group was significantly higher than that of the normal control group (P ＜ 0. 05). Conclusions Rat models of IUGR can be successfully established either by alcohol intervention, uterine artery ligation or low protein diet. The IUGR model established by low protein diet has the advantages of a higher incidence rate of IUGR and lower stillbirth rate, being more suitable for animal model research. As regards the catch-up growth, the average body mass of the rats during the postpartum period and lactation period after delivered by cesarean section in the group A and LP group is lower than that of the normal control group, but after lactation the rats grow faster than those in the normal control group, indicating the existence of a catch-up growth in the group A and LP group.