胰岛素样生长因子基因在小于胎龄鼠胎盘和胎肝组织中的动态表达变化

Dynamic expression changes of insulin-like growth factors gene in placental and hepatic tissue of small-for-gestational-age rat

目的:动态观察小于胎龄(small-for-gestational-age,SGA)鼠妊娠晚期胎盘及胎肝组织中胰岛素样生长因子-Ⅰ(insulin-like growth factor-I,IGF-I)及其结合蛋白(IGF binding proteins,IGFBPs)的基因表达变化,以探讨SGA的可能发病机制。方法:结扎子宫动脉(uterine arteries ligation,UAL)建立宫内发育迟缓(intrauterine growth retardation,I-UGR)模型,应用逆转录(RT)-PCR测定SGA鼠胚胎18、19、20、21天胎盘、肝脏组织IGF-I,IGFBPs mRNA表达变化,并与正常组比较。结果:(1)胎盘和胚胎重量随胎龄增加,两者呈正相关,同胎龄SGA组胎盘和胚胎重量均低于对照组;(2)胎盘和胎肝IGF-Ⅰ、IGFBP1、IGFBP2 mRNA表达均随胎龄增加而增加,胎盘中的表达均低于胎肝;(3)同胎龄SGA组胎盘和胎肝IGF-ⅠmRNA表达较对照组降低,而IGFBP1、IGFBP2 mRNA表达较对照组增加;⑷同胎龄SGA组胎盘和胎肝组织IGF-ⅠmRNA水平与胚胎重量成正相关,而IGFBP1、IGFBP2 mRNA水平与胚胎重量成负相关。结论:IGFs的表达存在组织差异性,妊娠晚期胎盘与胎肝组织IGFs mRNA表达水平紊乱可能与小于胎龄鼠不良的宫内生长有关。

Objective： In order to make an inquiry into the roles of insulin-like growth factor-I（IGF-I） and IGF binding proteins（IGFBPs） gene expression in the newborn small-for-gestational-age（SGA） rats,fetal hepatic and placental IGF-I and IGFBPs mRNA expressions were measured.Methods： The impacts of intrauterine growth retardation（IUGR） on uterine arteries ligation（UAL） were examined,IGF-I and IGFBPs mRNA contents were determined by RT-PCR in liver and placenta of SGA rats at different gestational ages,and they were compared with those in the control groups.Results：（1） The fetal and the placental weights increased with the gestational age.At the same gestational age,they were lighter than those in the control group,and the levels of fetal weights correlated positively with the placental weights.（2）The IGF-I,IGFBP1,IGFBP2 genes levels in fetal liver and placenta increased with gestational age.The level of IGF-I mRNA in SGA was lower than that of the control,but the levels of IGFBP1,IGFBP2 mRNA in the SGA were higher than those of the control.（3）The level of IGF-I mRNA in fetal rat liver and placenta correlated positively with fetal and placenta weight,but the levels of IGFBP1,IGFBP2 mRNA correlated negatively with fetal and placenta weight.Conclusions： The change of IGF-I and IGFBPs mRNA levels in fetal liver and placenta might result in fetal growth retardation.