Ashworth Morgan D, Ross Jason W, Hu Jianbo, White Frankie J, Stein Daniel R, Desilva Udaya, Johnson Gregory A, Spencer Thomas E, Geisert Rodney D
Department of Animal Science, Oklahoma Agricultural Experiment Station, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
Biol Reprod. 2006 Jun;74(6):1007-15. doi: 10.1095/biolreprod.105.046557. Epub 2006 Feb 1.
Porcine trophoblast attachment to the uterine surface is associated with increased conceptus and endometrial production of prostaglandins. Conceptus secretion of estrogen on Day 12 of gestation is important for establishment of pregnancy; however, early (Days 9 and 10) exposure to exogenous estrogens results in embryonic mortality. Present studies established the temporal and spatial pattern of endometrial PTGS1 (prostaglandin-endoperoxide synthase 1) and PTGS2 expression during the estrous cycle and early pregnancy and determined the effect of early estrogen treatment on endometrial PTGS expression in pregnant gilts. Endometrial PTGS1 mRNA expression increased 2- to 3-fold after Day 10 of the estrous cycle and pregnancy, whereas PTGS2 mRNA expression increased 76-fold between Days 5 and 15 of the estrous cycle and pregnancy. Increased expression of the PTGS2 transcript was detected in the lumenal epithelium after Day 10 in both cyclic and pregnant gilts. There was a 10- and 20-fold increase in endometrial PTGS2 protein expression between Days 5 and 18 of the estrous cycle and pregnancy respectively. Administration of estrogen on Days 9 and 10 of gestation increased endometrial PTGS2 mRNA and protein on Day 10, but decreased PTGS2 mRNA and protein in lumenal epithelium (LE) on Day 12 of gestation compared to vehicle-treated gilts. The present study demonstrates that an increase in uterine epithelial PTGS2 expression occurs after Day 10 of the estrous cycle and early pregnancy in the pig. The conceptus-independent increase in the uterine LE indicates that a novel pathway exists for endometrial induction PTGS2 expression before conceptus elongation and attachment to the uterine surface. Epithelial expression of PTGS2 may serve as one of the signals for placental attachment and embryo survival in the pig. Early administration of estrogen on Days 9 and 10 of pregnancy alters endometrial PTGS2 mRNA and protein expression, which may, at least in part, represent a mechanism by which endocrine disruption of pregnancy causes total embryonic loss during implantation in the pig.
猪滋养层与子宫表面的附着与孕体和子宫内膜前列腺素生成增加有关。妊娠第12天孕体分泌雌激素对妊娠建立很重要；然而，早期（第9天和第10天）暴露于外源性雌激素会导致胚胎死亡。目前的研究确定了发情周期和妊娠早期子宫内膜PTGS1（前列腺素内过氧化物合酶1）和PTGS2表达的时空模式，并确定了早期雌激素处理对妊娠母猪子宫内膜PTGS表达的影响。发情周期和妊娠第10天后，子宫内膜PTGS1 mRNA表达增加2至3倍，而发情周期和妊娠第5天至15天之间，PTGS2 mRNA表达增加76倍。在发情周期和妊娠的第10天后，在腔上皮中检测到PTGS2转录物表达增加。发情周期和妊娠第5天至18天之间，子宫内膜PTGS2蛋白表达分别增加了10倍和20倍。妊娠第9天和第10天给予雌激素可使第10天子宫内膜PTGS2 mRNA和蛋白增加，但与给予赋形剂处理的母猪相比，妊娠第12天腔上皮（LE）中的PTGS2 mRNA和蛋白减少。本研究表明，猪发情周期和妊娠早期第10天后，子宫上皮PTGS2表达增加。子宫LE中与孕体无关的增加表明，在孕体伸长并附着于子宫表面之前，存在一种新的子宫内膜诱导PTGS2表达的途径。PTGS2的上皮表达可能是猪胎盘附着和胚胎存活的信号之一。妊娠第9天和第10天早期给予雌激素会改变子宫内膜PTGS2 mRNA和蛋白表达，这可能至少部分代表了妊娠内分泌干扰导致猪植入期胚胎全部丢失的一种机制。
