Department of Animal Sciences,University of Florida,PO Box 110910,Gainesville,FL 32611-0910,USA.
Animal. 2018 Jun;12(s1):s104-s109. doi: 10.1017/S1751731118000083. Epub 2018 Feb 19.
Artificial insemination has been a landmark procedure in improving animal agriculture over the past 150 years. The utility of artificial insemination has facilitated a rapid improvement in animal genetics across agricultural species, leading to improvements of growth, health and productivity in poultry, swine, equine and cattle species. The utility of artificial insemination, as with all assisted reproductive technologies side-steps thousands of years of evolution that has led to the development of physiological systems to ensure the transmission of genetics from generation to generation. The perceived manipulation of these physiological systems as a consequence of assisted reproduction are points of interest in which research could potentially improve the success of these technologies. Indeed, seminal fluid is either removed or substantially diluted when semen is prepared for artificial insemination in domestic species. Although seminal fluid is not a requirement for pregnancy, could the removal of seminal fluid from the ejaculate have negative consequences on reproductive outcomes that could be improved to further the economic benefit of artificial insemination? One such potential influence of seminal fluid on reproduction stems from the question; how does the allogeneic foetus survive gestation in the face of the maternal immune system? Observation of the maternal immune system during pregnancy has noted maternal immune tolerance to paternal-specific antigens; a mechanism by which the maternal immune system tolerates specific paternal antigens expressed on the foetus. In species like human or rodent, implantation occurs days after fertilisation and as such the mechanisms to establish antigen-specific tolerance must be initiated very early during pregnancy. We and others propose that these mechanisms are initiated at the time of insemination when paternal antigens are first introduced to the maternal immune system. It is unclear whether such mechanisms would also be involved in domestic species, such as cattle, where implantation occurs weeks later in gestation. A new paradigm detailing the importance of paternal-maternal communication at the time of insemination is becoming evident as it relates to maternal tolerance to foetal antigen and ultimately pregnancy success.
人工授精在过去 150 年中一直是改善动物农业的一个里程碑式的程序。人工授精的应用促进了农业物种中动物遗传的快速改进，导致家禽、猪、马和牛的生长、健康和生产力得到提高。与所有辅助生殖技术一样，人工授精的应用绕过了几千年的进化，这导致了生理系统的发展，以确保遗传物质代代相传。由于辅助生殖，这些生理系统被认为是可以被操纵的，这是研究的关注点，研究可能会提高这些技术的成功率。事实上，在国内物种中，精液在准备人工授精时，要么去除要么大量稀释精液中的精子。尽管精液不是怀孕的必要条件，但从精液中去除精子是否会对生殖结果产生负面影响，而这些负面影响可以通过进一步提高人工授精的经济效益来改善？精液对生殖的潜在影响之一源于这样一个问题：在面对母体免疫系统的情况下，异基因胎儿如何在妊娠期间存活？对妊娠期间母体免疫系统的观察表明，母体免疫系统对父系特异性抗原具有免疫耐受；这是母体免疫系统对胎儿上表达的特定父系抗原耐受的一种机制。在人类或啮齿动物等物种中，植入发生在受精后几天，因此建立抗原特异性耐受的机制必须在妊娠早期就开始启动。我们和其他人提出，这些机制是在授精时启动的，当时父系抗原首次被引入母体免疫系统。目前还不清楚这些机制是否也会参与到牛等家畜中，因为在妊娠的后期，植入发生在数周后。一个新的范例详细说明了授精时父-母沟通的重要性，因为它与母体对胎儿抗原的耐受性以及最终的妊娠成功有关。
