The biology of early pregnancy in the mare

母马早期妊娠的生物学

• 批准号: 3342-2007
• 负责人: Betteridge, Keith
• 金额: $ 2.49万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Group
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=473691
• 关键词: biology; early; pregnancy; mare

Our research aims at understanding the interactions of the very young equine embryo with its environment in the uterus of the mare during the first month of pregnancy, a time when 10-20% of pregnancies are lost for reasons that we don't understand. The success and failure of early pregnancy is of fundamental and economic importance in all the domestic animals but the horse is an especially good species in which to study its underlying physiology; the equine embryo can be flushed from the uterus throughout the second to fourth weeks without harming the mare and, also, has structural and functional features that are not found in the embryos of other species. One such feature is the embryo's production and use of steroid hormones that we believe to be very important in influencing its local environment. This 'steroidogenesis' and steroid metabolism is being studied in detail. Another unusual feature is a thin, tough, transparent capsule that envelops the hollow ball of cells (the conceptus) as it expands rapidly from a diameter of less that 0.2 mm to one of more than 20 mm during its first two weeks in the uterus. Having described the biochemical makeup of the capsule, we now want to test our idea that it is vital for attaching the conceptus to the lining of the uterus (the endometrium) where the placenta will later develop. We think that this adhesion involves particular sugar molecules in the capsule and protein molecules on the endometrium and will test this notion using the very latest biochemical and molecular techniques on tissues collected from pregnant mares. In order to discover what goes wrong when pregnancy fails, we use a model system of 'compromised' pregnancy; at the end of the second week of pregnancy we treat some mares with a prostaglandin that reduces progesterone production by the ovary. Despite the treatment, the conceptus can survive in the uterus for another 3-4 days after which it is recovered and compared with conceptuses from 'control' mares not treated with prostaglandin. The comparisons of conceptuses and uterine materials from normal and compromised pregnancies are gradually enabling us to pinpoint the differences in proteins and steroid hormone activities that are associated with pregnancy failure.

我们的研究旨在了解怀孕第一个月期间非常年轻的马胚胎与母马子宫内环境的相互作用，此时10-20%的怀孕因我们不了解的原因而丢失。早期妊娠的成功和失败对所有家畜都具有重要的基础和经济意义，但马是研究其潜在生理学的特别好的物种;马的胚胎可以在第二至第四周从子宫中冲洗出来，而不会伤害母马，而且，在其他物种的胚胎中没有发现结构和功能特征。其中一个特征是胚胎产生和使用类固醇激素，我们认为这对影响其局部环境非常重要。这种“类固醇生成”和类固醇代谢正在详细研究中。另一个不寻常的特征是一个薄的，坚韧的，透明的胶囊包裹着中空的细胞球（孕体），因为它在子宫内的前两周内从直径不到0.2 mm迅速膨胀到超过20 mm。在描述了胶囊的生化组成之后，我们现在想测试我们的想法，即它对于将孕体附着在子宫内膜（子宫内膜）上至关重要，胎盘将在子宫内膜上发育。我们认为这种粘附涉及包膜中的特定糖分子和子宫内膜上的蛋白质分子，并将使用最新的生物化学和分子技术在从妊娠子宫内膜收集的组织上测试这一概念。 为了发现怀孕失败时出现的问题，我们使用了一个“妥协”怀孕的模型系统;在怀孕的第二周结束时，我们用前列腺素治疗一些卵巢，减少卵巢孕酮的产生。 尽管进行了治疗，但孕体仍能在子宫内存活3-4天，然后恢复，并与未用前列腺素治疗的“对照”孕体进行比较。 比较正常妊娠和妊娠受损妊娠的孕体和子宫材料，逐渐使我们能够确定与妊娠失败相关的蛋白质和类固醇激素活性的差异。