Department of Biomedical & Clinical Sciences (BKV), BKH/Obstetrics & Gynecology, Faculty of Medicine and Health Sciences, Linköping University, SE-58185 Linköping, Sweden.
Department of Medicine and Animal Surgery, Faculty of Veterinary Medicine, International Excellence Campus for Higher Education and Research "Campus Mare Nostrum", University of Murcia, Murcia, Spain.
Anim Reprod Sci. 2022 Sep;244:107051. doi: 10.1016/j.anireprosci.2022.107051. Epub 2022 Aug 3.
Seminal plasma (SP) is not a pre-requisite for pregnancy. Yet, this heterogeneous, composite SP has proven relevant for fertility, as mediator for cell-to-cell communication between producing cells, spermatozoa and the female internal genital tract, regulating complex reproductive processes. Bearing hormones, proteins, cytokines as well as nuclei acids in nano-sized lipid bilayer seminal extracellular vesicles (sEVs), the SP concerts signaling to the female. Signals influence timing of ovulation, sperm transport and, particularly, enable the female immune system to balance her cryptic choice to engage into pregnancy or reject an eventual fertilization. This essay, focusing on livestock in general and pigs in particular, discusses the intrinsic roles of sEVs with regards to reproductive homeostasis, while binding and internalizing their cargo in spermatozoa and female tract epithelia to regulate their functional activity. Since prior studies had inconclusive results using bulk SP or single SP-contained free molecules, argumentation is hereby provided to increase the current incipient research on livestock sEVs, where fragile molecules relevant for fertility are shielded from degradation during handling. Seminal EVs isolated from SP can be used for andrological diagnosis and perhaps to select breeders with optimal fertility. Moreover, sEVs can be laboratory-uploaded with specific molecules or even engineered as lipid nanodroplets used as additives for extenders to improve fertility after artificial insemination (AI) or reproductive biotechnologies.
精浆（SP）并不是妊娠的必要条件。然而，这种异质的复合 SP 已被证明与生育能力有关，它作为产生细胞、精子和女性生殖道内细胞间通讯的介质，调节着复杂的生殖过程。SP 中的纳米级脂质双层外泌体（sEVs）中含有激素、蛋白质、细胞因子和核核酸，为女性提供信号。这些信号影响排卵时间、精子运输，特别是使女性免疫系统能够平衡她的隐性选择，即参与妊娠或拒绝可能的受精。本文主要关注家畜，特别是猪，讨论了 sEVs 对于生殖稳态的内在作用，同时结合并内化它们在精子和女性生殖道上皮细胞中的货物，以调节它们的功能活性。由于之前使用大量 SP 或单一 SP 包含的游离分子进行的研究结果不一致，因此本文提供了更多证据来增加目前对家畜 sEVs 的研究，这些脆弱的与生育能力相关的分子在处理过程中受到保护，不会降解。从 SP 中分离出来的精子 EVs 可用于男科诊断，并可能选择具有最佳生育能力的繁殖者。此外，sEVs 可以在实验室中上传特定分子，甚至可以设计为作为纳米脂质滴添加到稀释剂中，以提高人工授精（AI）或生殖生物技术后的生育能力。
