The sperm reservoir is formed after insemination in mammals, allowing sperm storage in the oviduct until their release. We previously showed that physiological concentrations of progesterone (P4) trigger in vitro the sperm release from bovine oviductal epithelial cells (BOECs), selecting a subpopulation of spermatozoa with a higher fertilizing competence. Here, by using Western-Blot, confocal microscopy and Intact Cell MALDI-TOF-Mass Spectrometry strategies, we elucidated the changes derived by the P4-induced release on sperm cells (BOEC-P4 spz). Our findings show that, compared to controls, BOEC-P4 spz presented a decrease in the abundance of Binder of Sperm Proteins (BSP) -3 and -5, suggesting one mechanism by which spermatozoa may detach from BOECs, and thus triggering the membrane remodeling with an increase of the sperm membrane fluidity. Furthermore, an interesting number of membrane lipids and proteins were differentially abundant in BOEC-P4 spz compared with controls.

中文翻译：

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孕酮通过修饰精子蛋白质组学，脂质组学和膜流动性来诱导从输卵管上皮细胞释放精子。

精子储库是在哺乳动物体内进行授精后形成的，可以将精子储存在输卵管中直至其释放。我们以前表明，孕酮（P4）的生理浓度在体外触发了从牛输卵管上皮细胞（BOECs）释放出的精子，从而选择了具有较高受精能力的精子亚群。在这里，通过使用蛋白质印迹，共聚焦显微镜和完整细胞MALDI-TOF-质谱分析策略，我们阐明了由P4诱导的精子细胞释放（BOEC-P4 spz）引起的变化。我们的研究结果表明，与对照相比，BOEC-P4 spz降低了精子蛋白结合剂（BSP）-3和-5的丰度，这表明一种机制可能使精子脱离BOEC，从而触发了膜的重塑随着精子膜流动性的增加。