Department of Animal Sciences and Institute of Genomic Biology, University of Illinois at Urbana-Champaign, 1207 West Gregory Drive, Urbana, IL, 61801, USA.
Department of Veterinary Medicine, Western Santa Catarina University, Xanxere, Brazil.
Sci Rep. 2019 Dec 20;9(1):19546. doi: 10.1038/s41598-019-55834-z.
Sperm storage in the female reproductive tract after mating and before ovulation is a reproductive strategy used by many species. When insemination and ovulation are poorly synchronized, the formation and maintenance of a functional sperm reservoir improves the possibility of fertilization. In mammals, the oviduct regulates sperm functions, such as Ca influx and processes associated with sperm maturation, collectively known as capacitation. A fraction of the stored sperm is released by unknown mechanisms and moves to the site of fertilization. There is an empirical association between the hormonal milieu in the oviduct and sperm detachment; therefore, we tested directly the ability of progesterone to induce sperm release from oviduct cell aggregates. Sperm were allowed to bind to oviduct cells or an immobilized oviduct glycan and then challenged with progesterone, which stimulated the release of 48% of sperm from oviduct cells or 68% of sperm from an immobilized oviduct glycan. The effect of progesterone on sperm release was specific; pregnenolone and 17α-OH-progesterone did not affect sperm release. Ca influx into sperm is associated with capacitation and development of hyperactivated motility. Progesterone increased sperm intracellular Ca, which was abrogated by blocking the sperm-specific Ca channel CatSper with NNC 055-0396. NNC 055-0396 also blocked the progesterone-induced sperm release from oviduct cells or immobilized glycan. An inhibitor of the non-genomic progesterone receptor that activates CatSper similarly blocked sperm release. This is the first report indicating that release of sperm from the sperm reservoir is induced by progesterone action through CatSper channels.
交配后和排卵前精子在雌性生殖道中的储存是许多物种使用的一种生殖策略。当受精和排卵不同步时，形成和维持功能性精子库可以提高受精的可能性。在哺乳动物中，输卵管调节精子的功能，如钙离子内流和与精子成熟相关的过程，统称为获能。一部分储存的精子通过未知机制释放并移动到受精部位。输卵管中的激素环境与精子脱离之间存在经验性关联；因此，我们直接测试了孕激素诱导输卵管细胞聚集体中精子释放的能力。允许精子与输卵管细胞或固定的输卵管糖结合，然后用孕激素刺激，这刺激了 48%的精子从输卵管细胞或 68%的精子从固定的输卵管糖中释放。孕激素对精子释放的影响是特异性的；孕烯醇酮和 17α-OH-孕酮不会影响精子释放。精子内钙离子内流与获能和超激活运动的发展有关。孕激素增加了精子的细胞内钙，用 NNC 055-0396 阻断精子特异性钙通道 CatSper 可以阻断这一过程。NNC 055-0396 还阻断了孕激素诱导的输卵管细胞或固定糖从输卵管细胞中释放精子。激活 CatSper 的非基因组孕激素受体的抑制剂也同样阻断了精子的释放。这是第一个表明孕激素通过 CatSper 通道诱导精子从精子库释放的报告。
