Simmons Rebecca M, Erikson David W, Kim Jinyoung, Burghardt Robert C, Bazer Fuller W, Johnson Greg A, Spencer Thomas E
Department of Animal Science, Texas A&M University, College Station, Texas 77843, USA.
Endocrinology. 2009 Sep;150(9):4295-305. doi: 10.1210/en.2009-0060. Epub 2009 Jun 4.
Establishment of pregnancy in ruminants requires conceptus elongation and production of interferon-tau (IFNT), the pregnancy recognition signal that maintains ovarian progesterone (P4) production. These studies determined temporal and spatial alterations in IGF binding protein (IGFBP)-1 and IGFBP3 in the ovine and bovine uterus; effects of P4 and IFNT on their expression in the ovine uterus; and effects of IGFBP1 on ovine trophectoderm cell proliferation, migration, and attachment. IGFBP1 and IGFBP3 were studied because they are the only IGFBPs specifically expressed by the endometrial luminal epithelia in sheep. In sheep, IGFBP1 and IGFBP3 expression was coordinate with the period of conceptus elongation, whereas only IGFBP1 expression was coordinate with conceptus elongation in cattle. IGFBP1 mRNA in the ovine endometria was between 5- and 29-fold more abundant between d 12 and 16 of pregnancy compared with the estrous cycle and greater on d 16 of pregnancy than nonpregnancy in the bovine uterus. In sheep, P4 induced and IFNT stimulated expression of IGFBP1 but not IGFBP3; however, the effect of IFNT did not mimic the abundant increase observed in pregnant ewes. Therefore, IGFBP1 expression in the endometrium is regulated by another factor from the conceptus. IGFBP1 did not affect the proliferation of ovine trophectoderm cells in vitro but did stimulate their migration and mediate their attachment. These studies reveal that IGFBP1 is a common endometrial marker of conceptus elongation in sheep and cattle and most likely regulates conceptus elongation by stimulating migration and attachment of the trophectoderm.
反刍动物怀孕的建立需要胚胎伸长并产生干扰素-τ（IFNT），IFNT是维持卵巢孕酮（P4）分泌的妊娠识别信号。这些研究确定了绵羊和牛子宫中胰岛素样生长因子结合蛋白（IGFBP）-1和IGFBP3的时空变化；P4和IFNT对其在绵羊子宫中表达的影响；以及IGFBP1对绵羊滋养外胚层细胞增殖、迁移和附着的影响。对IGFBP1和IGFBP3进行研究是因为它们是绵羊子宫内膜腔上皮细胞特异性表达的仅有的IGFBPs。在绵羊中，IGFBP1和IGFBP3的表达与胚胎伸长时期相协调，而在牛中只有IGFBP1的表达与胚胎伸长相协调。与发情周期相比，妊娠第12至16天绵羊子宫内膜中IGFBP1 mRNA的丰度高5至29倍，且在妊娠第16天牛子宫中IGFBP1 mRNA的丰度高于未怀孕时。在绵羊中，P4诱导并使IFNT刺激IGFBP1的表达，但不刺激IGFBP3的表达；然而，IFNT的作用并未模拟怀孕母羊中观察到的大量增加。因此，子宫内膜中IGFBP1的表达受胚胎中另一种因子的调节。IGFBP1在体外不影响绵羊滋养外胚层细胞的增殖，但确实刺激其迁移并介导其附着。这些研究表明，IGFBP1是绵羊和牛胚胎伸长的常见子宫内膜标志物，很可能通过刺激滋养外胚层的迁移和附着来调节胚胎伸长。
