Department of Animal Sciences, Center for Reproductive Biology, Washington State University, Pullman, Washington, USA.
Reproduction. 2013 Aug 21;146(4):377-87. doi: 10.1530/REP-13-0165. Print 2013 Oct.
In cattle, the blastocyst hatches from the zona pellucida on days 8-9 and then forms a conceptus that grows and elongates into an ovoid and then filamentous shape between days 9 and 16. The growing conceptus synthesizes and secretes prostaglandins (PGs) and interferon τ (IFNT). Our hypothesis was that the ovoid conceptus exerts a local effect on the endometrium prior to maternal recognition of pregnancy on day 16 in cattle. In study one, synchronized cyclic heifers received no blastocysts or 20 in vitro-produced blastocysts on day 7 and their uteri were collected on day 13. IFNT was not detected by RIA in the uterine flushing samples of pregnant heifers containing multiple ovoid conceptuses; however, total PG levels were higher in the uterine lumen of pregnant heifers than in that of cyclic heifers. Microarray analysis revealed that the expression of 44 genes was increased in the endometria of day 13 pregnant heifers when compared with that in the endometria of cyclic heifers, and many of these genes were classical Type I IFN-stimulated genes (ISGs). In studies two and three, the effects of infusing PGs at the levels produced by the elongating day 14 conceptus into the uterine lumen of cyclic ewes on ISG expression in the endometrium were determined. Results indicated that the infusion of PGs increased the abundance of several ISGs in the endometrium. These studies support the hypothesis that the day 13 conceptus secretes PGs that act locally in a paracrine manner to alter gene expression in the endometrium prior to pregnancy recognition in cattle.
在牛中，囊胚于第 8-9 天从透明带孵出，然后形成一个胚胎，在第 9-16 天之间生长并延长成卵圆形，然后是丝状。生长的胚胎合成并分泌前列腺素（PGs）和干扰素τ（IFNT）。我们的假设是，在牛第 16 天母体能识别怀孕之前，卵圆形胚胎对子宫内膜有局部作用。在研究一中，同步化的循环小母牛在第 7 天没有接受胚胎或接受 20 个体外产生的胚胎，它们的子宫在第 13 天被收集。在含有多个卵圆形胚胎的怀孕小母牛的子宫冲洗样本中，RIA 未检测到 IFNT；然而，怀孕小母牛的子宫腔中总 PG 水平高于循环小母牛。微阵列分析显示，与循环小母牛的子宫内膜相比，第 13 天怀孕小母牛的子宫内膜中 44 个基因的表达增加，其中许多基因是经典的 I 型干扰素刺激基因（ISGs）。在研究二和研究三中，确定将在生长中的第 14 天胚胎产生的 PG 水平注入循环母羊子宫腔对子宫内膜中 ISG 表达的影响。结果表明，PG 的输注增加了子宫内膜中几个 ISG 的丰度。这些研究支持这样的假设，即第 13 天的胚胎分泌 PGs，以旁分泌的方式在怀孕识别之前在局部起作用，改变牛的子宫内膜中的基因表达。
