van der Weijden V A, Ulbrich S E
ETH Zurich, Animal Physiology, Institute of Agricultural Sciences, Switzerland.
ETH Zurich, Animal Physiology, Institute of Agricultural Sciences, Switzerland.
Theriogenology. 2020 Dec;158:105-111. doi: 10.1016/j.theriogenology.2020.06.042. Epub 2020 Jul 6.
An alarming number of large mammalian species with low reproduction rates is threatened with extinction. As basic knowledge of reproductive physiology is currently lacking in many species, increasing the understanding of reproductive physiology is imperative and includes the development of novel artificial reproduction technologies. Despite the relatively comprehensive knowledge on molecular mechanisms underlying reproduction in livestock species such as cattle, pregnancy failures are likewise far from understood. Contrary to other wildlife species, the European roe deer (Capreolus capreolus) displays a remarkably high pregnancy rate. In parts, cattle and roe deer exhibit comparable features of preimplantation embryo development. Therefore, understanding the high fertility rate in the roe deer holds a great potential for cross-species knowledge gain. As the only known species among the artiodactylae, the roe deer displays a long period of embryonic diapause. The preimplantation blastocyst reaches a diameter of 1 mm only at around 4 months compared to around 13 days post estrus in cattle. The expanded blastocyst survives in a uterine microenvironment that contains a unique set of yet unidentified factors that allow embryonic stem cells to proliferate at low pace without impairing their developmental potential. Upon reactivation, intimate embryo-maternal communication comparable to those reported in cattle is thought to occur. In this review, current knowledge, parallels and differences of reproductive physiology in cattle and roe deer are reviewed. The roe deer is proposed as a unique model species to (1) enhance our knowledge of fertility processes, (2) define factors that support embryo survival for an extended period, (3) advance knowledge on embryonic stem cells, and (4) unravel potential implications for the development of novel strategies for artificial reproductive technologies.
大量繁殖率低的大型哺乳动物物种正面临灭绝的威胁。由于目前许多物种缺乏生殖生理学的基础知识，因此加深对生殖生理学的理解势在必行，这包括开发新型人工繁殖技术。尽管对牛等家畜物种繁殖的分子机制已有相对全面的了解，但妊娠失败同样远未被理解。与其他野生动物物种不同，欧洲狍（Capreolus capreolus）的妊娠率非常高。在某些方面，牛和狍在植入前胚胎发育方面表现出可比的特征。因此，了解狍的高繁殖力对于跨物种知识获取具有巨大潜力。作为偶蹄目中唯一已知的物种，狍表现出长时间的胚胎滞育。与牛在发情后约13天相比，植入前囊胚仅在约4个月时达到1毫米的直径。扩张的囊胚在子宫微环境中存活，该微环境包含一组独特的尚未确定的因素，这些因素允许胚胎干细胞以低速度增殖而不损害其发育潜力。重新激活后，据认为会发生与牛中报道的类似的亲密胚胎-母体通讯。在这篇综述中，回顾了牛和狍生殖生理学的现有知识、异同点。狍被提议作为一种独特的模式物种，以（1）增强我们对繁殖过程的了解，（2）确定支持胚胎长期存活的因素，（3）推进关于胚胎干细胞的知识，以及（4）揭示对新型人工繁殖技术策略发展的潜在影响。
