Equine Embryonic, Luteal and Endometrial Interactions in Pregnancy Recognition

黄体、子宫和胚胎组织参与母马的母体妊娠识别(MRP)，但其发生的详细机制仍未解决。马的早期怀孕失败是经济损失的一个原因，影响了超过10%的马怀孕。马的高妊娠率是怀孕识别研究的一个令人信服的原因。为了防止早孕丢失，需要了解母马母体识别怀孕(MRP)所涉及的因素及其调节。我们的研究集中在检测催产素(Oxy)的作用，以及在马MRP中代谢Oxy的酶，称为催产素酶(OTase)。我们报道了OTase存在于未怀孕和怀孕母马的血清中。我们确定OTase的水平不受孕酮(P4)的调节，因为水平不会随着P4水平的下降而变化。组织中存在高水平的OTase(U/g组织)，免疫组织化学显示OTase存在于子宫内膜上皮、子宫肌层和胎盘组织中。催产素在母体行为、排乳、子宫收缩和胎盘分娩中起着核心作用。Oxy的全身性水平受到OTase快速清除机制的严格调控。我们将研究OTNP-1向Oxy的转化，进一步阐明Oxy在MRP中的作用。催产素通过其受体作用，已知可增加其他组织中前列腺素(PG)的分泌。MRP需要排卵后5-15天的胚胎移位。催产素、OTase和PG可能参与了胚胎的迁移。我们将对用不同的PG抑制剂治疗的怀孕母马进行比较，已知这些抑制剂会影响胚胎的流动性。我们将应用：子宫内膜、胚胎和黄体组织的分子研究；超声成像工具；以及激素分析。我们将在排卵后第10天研究未怀孕的母马，用生理盐水、雌激素、氧、前列腺素F、前列腺素E、前列腺素E和前列腺素F宫内脉冲治疗，以模拟自然。拦截或改变PG的脉冲，或PGE PGE比率，被认为影响黄体功能，这是MRP的关键。将确定治疗对P4、黄体组织、激素、基因表达和蛋白质的影响。我们还将使用排卵后不同天的黄体和子宫内膜细胞的体外培养来鉴定MRP调节信号。细胞将用受精卵条件培养液、激素、抑制剂和激动剂处理。治疗效果将通过对基因和蛋白质的分子分析以及各种激素的分泌来检验。然后将探索可能的调节物质的潜在分子作用机制。通过这些不同的方法，我们将能够确定影响胚胎流动性、黄体功能和与MRP相关的调控途径的调控因素。这些信息将被应用于开发旨在减少母马早期妊娠损失的治疗方法。

Luteal, uterine and embryonic tissues are involved in the maternal recognition of pregnancy (MRP) in mares, but the detailed mechanism of how this occurs, remains unsolved. Early pregnancy failure in horses is a cause of economic loss and affects more than 10% of equine pregnancies. This high rate of equine pregnancy loss is a compelling cause for research in pregnancy recognition. An understanding of the factors involved in the maternal recognition of pregnancy (MRP) in mares, and their regulation, is required to prevent early pregnancy losses. Our research has concentrated on examining the role of oxytocin (Oxy), and the enzyme that metabolizes Oxy, called oxytocinase (OTase) in equine MRP. We reported that OTase is present in serum in non-pregnant and pregnant mares. We determined that levels of OTase are not regulated by progesterone (P4), as levels do not vary as P4 levels decline. There are high levels of OTase (U/g tissue) in tissues, and immunohistochemistry reveals that OTase is present in endometrial epithelium; myometrium; and placental tissue. Oxytocin has a central role in: maternal behaviour, milk ejection, uterine contraction, and placental delivery. Systemic levels of Oxy are tightly regulated by rapid clearance mechanisms involving OTase. We will study the conversion of OTNP-1 to Oxy, and further clarify the role of Oxy in MRP. Oxytocin acting through its receptor, is know to increase prostaglandin (PG) secretion in other tissues. Embryo mobility from day 5-15 post-ovulation is required for MRP. Oxytocin, OTase and PG are likely involved in embryo mobility. We will compare pregnant mares that are treated with different PG inhibitors known to effect embryo mobility. We will apply: molecular studies of endometrial, embryonic and luteal tissues; ultrasound imaging tools; and hormone assays. We will study non-pregnant mares on day 10 after ovulation, treated with intrauterine pulses of: saline, estrogen, Oxy, PGF, PGE, and PGE and PGF to mimic nature. Intercepting or changing the pulses of PG, or the PGE PGE ratio, is thought to affect luteal function, which is key for MRP. The effects of treatment on P4, luteal tissue, hormones, gene expression and proteins will be determined. We will also identify MRP regulatory signals by using in vitro cultures of luteal and endometrial cells from different days post-ovulation. Cells will be treated with conceptus conditioned media, hormones, inhibitors and agonists. Treatment effects will be examined using molecular analyses of genes and proteins, and secretion of various hormones. Possible regulatory substances will then be explored for their underlying molecular mechanism of action. We will, through these diverse approaches, be able to identify regulatory factors that influence embryo mobility, luteal function and the regulatory pathways associated with MRP. This information will be applied to develop therapies aimed at decreasing early pregnancy loss in mares.