Inclusion and exclusion criteria summary.

BackgroundThe steroid hormones progesterone (P4) and Estrogen (E2) are essential for reproduction in both male and female mammals. Steroid hormones can alter sperm function in vitro via several mechanisms, thereby facilitating fertilization of female germ cells. The purpose of this systematic review is to investigate the in vitro experimental models that are used to understand the functionality of sperm after receiving supplementation with E2 and P4 in samples obtained from animal species using sperm oviductal epithelial cells (OECs) co-cultures and cultures of sperm in culture media only without OECs.MethodologyA systematic literature search was conducted using Web of Science, Google Scholar, and PubMed to examine in vitro experimental models involving E2 and P4, aiming to understand sperm functionality in animals with or without OECs in culture media. A total of 32 out of 660 retrieved articles met the inclusion criteria, from which data were extracted, synthesized, and presented in a descriptive format.ResultsSperm and oviducts from hamsters, mice, rats, monkeys, porcine, ovine, and bovine were used. Steroids E2 and P4 were administered at varying doses, either individually or in combination, with several studies observing dose-dependent effects on sperm function. In sperm-OECs co-cultures, P4 consistently promoted sperm hyperactivation, capacitation, and acrosome reaction (AR) via CatSper channel mechanisms, facilitating sperm release from OECs. Contrastingly, E2 delayed capacitation while enhancing sperm binding to the OECs. Similarly, supplementation of P4 in culture media alone without OECs induced sperm AR and capacitation, altered sperm motility, and improved in vitro fertilization (IVF) rates. Variations in motility and the binding ability of sperm to the isthmus and ampulla were reported in some studies.ConclusionThe in vitro studies revealed that E2 and P4 alter sperm behavior dependent on dose, and improve sperm fertilizing ability in IVF programs across species. Future studies should focus on investigating and clarifying the species-specific sperm mechanisms following steroid hormone supplementation to enhance our understanding and improve the assisted reproductive technology outcomes.研究背景：类固醇激素孕酮（progesterone, P4）与雌激素（Estrogen, E2）对雌雄哺乳动物的繁殖活动均具有关键作用。类固醇激素可通过多种机制在体外调控精子功能，进而促进雌性生殖细胞的受精过程。本系统综述旨在探究相关体外实验模型，此类模型用于研究动物来源样本中，经E2与P4处理后的精子功能，实验体系分为两类：精子与输卵管上皮细胞（Oviductal Epithelial Cells, OECs）共培养体系，以及不含OECs的单纯精子培养基培养体系。 研究方法：本研究通过Web of Science、Google Scholar及PubMed开展系统性文献检索，以考察涉及E2与P4的体外实验模型，旨在探究动物来源样本中，在有或无OECs的培养基环境下的精子功能。最终从检索获得的660篇文献中筛选出32篇符合纳入标准的文献，对其中的数据进行提取、综合，并以描述性形式呈现研究结果。 研究结果：本研究使用了仓鼠、小鼠、大鼠、猴、猪、绵羊及牛的精子与输卵管组织。实验中以不同剂量单独或联合施用类固醇激素E2与P4，多项研究观察到其对精子功能存在剂量依赖性影响。在精子-OECs共培养体系中，P4可通过CatSper通道通路持续促进精子超激活、获能及顶体反应（Acrosome Reaction, AR），并推动精子从OECs上脱离。与之相反，E2会延缓精子获能，但增强精子与OECs的结合能力。类似地，在不含OECs的单纯培养基中添加P4，可诱导精子发生顶体反应与获能、改变精子活力，并提升体外受精（In Vitro Fertilization, IVF）成功率。部分研究还报道了精子活力以及精子与输卵管峡部、壶腹部结合能力的差异变化。 研究结论：现有体外研究表明，E2与P4可通过剂量依赖性方式调控精子行为，并提升跨物种体外受精程序中的精子受精能力。未来研究应聚焦于探究并阐明类固醇激素处理后物种特异性的精子作用机制，以加深相关认知并改善辅助生殖技术的临床结局。