Vodstrcil Lenka A, Wlodek Mary E, Parry Laura J
Department of Zoology, University of Melbourne, Parkville, Vic. 3010, Australia.
Reprod Fertil Dev. 2007;19(4):530-8. doi: 10.1071/rd07007.
The peptide hormone relaxin stimulates uterine growth and endometrial angiogenesis and inhibits myometrial contractions in a variety of species. The receptor for relaxin is a leucine-rich repeat containing G-protein-coupled receptor Lgr7 (RXFP1) that is highly expressed in the myometrium of late pregnant mice, with a significant decrease in receptor density observed at term. The present study first compared the expression of Lgr7 with another relaxin-family receptor Lgr8 (RXFP2) in the uterus and placenta of late pregnant rats. The uterus was separated into endometrial and myometrial components, and the myometrium into fetal and non-fetal sites, for further analysis. We then assessed the response of these receptors to uteroplacental restriction (UPR). Expression of the Lgr7 gene was significantly higher in the uterus compared with the placenta. Within the uterus, on Day 20 of gestation, there was equivalent expression of Lgr7 in fetal and non-fetal sites of the myometrium, as well as in the endometrium v. myometrium. The second receptor investigated, Lgr8, was also expressed in the endometrium and myometrium, but at significantly lower levels than Lgr7. Bilateral ligation of the maternal uterine blood vessels on Day 18 of gestation resulted in uteroplacental restriction, a decrease in fetal weight and litter size, and a significant upregulation in uterine, but not placental, Lgr7 and Lgr8 gene expression in UPR animals compared with controls. These data suggest that both relaxin family receptors are upregulated in response to a reduction in uteroplacental blood flow in rats.
肽类激素松弛素可刺激多种物种的子宫生长和子宫内膜血管生成，并抑制子宫肌层收缩。松弛素的受体是富含亮氨酸重复序列的G蛋白偶联受体Lgr7（RXFP1），该受体在妊娠晚期小鼠的子宫肌层中高度表达，足月时受体密度显著降低。本研究首先比较了妊娠晚期大鼠子宫和胎盘中Lgr7与另一种松弛素家族受体Lgr8（RXFP2）的表达。将子宫分为子宫内膜和子宫肌层部分，将子宫肌层分为胎儿部位和非胎儿部位，以进行进一步分析。然后，我们评估了这些受体对子宫胎盘血流受限（UPR）的反应。与胎盘相比，子宫中Lgr7基因的表达显著更高。在子宫内，妊娠第20天时，子宫肌层的胎儿部位和非胎儿部位以及子宫内膜与子宫肌层中Lgr7的表达相当。所研究的第二种受体Lgr8也表达于子宫内膜和子宫肌层，但表达水平明显低于Lgr7。妊娠第18天对母体子宫血管进行双侧结扎导致子宫胎盘血流受限、胎儿体重和窝仔数减少，与对照组相比，UPR动物子宫中Lgr7和Lgr8基因表达显著上调，但胎盘中未上调。这些数据表明，在大鼠中，两种松弛素家族受体均会因子宫胎盘血流减少而上调。
