208 Sperm Retention, Storage and Release from the Oviduct: A Story of Sugars, Steroids, and Channels

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 113-114
Author(s):  
David J Miller

Abstract Because mating is not always synchronized with ovulation, females from many species store sperm in the female reproductive tract until ovulation and fertilization. This may be done for short periods, a day or two for swine and cattle, or longer periods. Other mammals, such as some species of bats, store sperm for several months. Chickens and turkeys store sperm for 2–4 weeks and queens of some species of insects store sperm for over a decade in specialized structures. How sperm are retained, kept fertile for varying times and released is unclear. We have identified two specific carbohydrate motifs that are abundant in the porcine oviduct that bind and retain sperm in the isthmus. When immobilized, these two glycans lengthen sperm lifespan and suppress the normal increase in intracellular Ca2+ that normally accompanies capacitation. Porcine sperm can be released from oviduct cells and immobilized glycans by progesterone, perhaps of ovarian or cumulus-oocyte complex origin, which activates CatSper, a sperm-specific Ca2+ channel. Progesterone, as well as other compounds that stimulate hyperactivated motility, trigger sperm release, suggesting that hyperactivated motility is sufficient to release porcine sperm from oviduct glycans. We also have found that blocking proteasome-induced sperm protein lysis diminishes the number of sperm released from oviduct glycans. Finally, a transcriptomic approach has identified several groups of genes that are differentially regulated in both bovine and porcine oviducts from estrus animals that are storing sperm compared to oviducts from diestrus animals. This provides clues about how sperm lifespan is extended during storage.

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 188-188
Author(s):  
David J Miller

Abstract After semen deposition, a fraction of sperm is transported through the female reproductive tract to the lower oviduct, the isthmus, where sperm are retained to form a reservoir. Some of these sperm are released to move to the upper oviduct, the site of fertilization. For sperm to make this journey, they must overcome challenges including possible phagocytosis, high fluid viscosity, and peristaltic contractions of the tract. The study of sperm transport is complex because so few sperm reach the site of fertilization. We have focused our studies on how sperm are retained in the reservoir, how storage prolongs sperm lifespan, and how sperm are released to fertilize oocytes. Sperm storage is particularly important in situations in which ovulation is not tightly synchronized with semen deposition. This occurs in domestic animals, but is especially notable in some species of bats, birds, and insects. Using porcine sperm and an array of 400 common glycans, we identified two specific glycan motifs found in all structures that bound sperm, a Lewis X trisaccharide and a branched 6-sialylated oligosaccharide. Tandem MS profiling indicated that both motifs were abundant in the asparagine-linked glycans of the oviduct epithelium and several larger oligosaccharides were identified that contained both motifs. When these motifs were immobilized, each could retain sperm, suppress Ca2+ influx and lengthen sperm lifespan. Secretions from the cumulus-oocyte complex (COC) and progesterone released sperm from immobilized oviduct glycans, suggesting that COCs can themselves signal sperm release. Progesterone-induced release required CatSper channels, sperm hyperactivation and was dependent on sperm protein degradation. These studies support a model in which sperm are retained in the isthmus by specific glycans on the epithelium, which extends sperm lifespan until COCs produce releasing factors that promote sperm liberation from the isthmus and movement to the ampulla to fertilize the COCs.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sergio A. Machado ◽  
Momal Sharif ◽  
Huijing Wang ◽  
Nicolai Bovin ◽  
David J. Miller

AbstractSperm 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 Ca2+ 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. Ca2+ influx into sperm is associated with capacitation and development of hyperactivated motility. Progesterone increased sperm intracellular Ca2+, which was abrogated by blocking the sperm–specific Ca2+ 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.


Author(s):  
Mai M. Said ◽  
Ramesh K. Nayak ◽  
Randall E. McCoy

Burgos and Wislocki described changes in the mucosa of the guinea pig uterus, cervix and vagina during the estrous cycle investigated by transmission electron microscopy. More recently, Moghissi and Reame reported the effects of progestational agents on the human female reproductive tract. They found drooping and shortening of cilia in norgestrel and norethindrone- treated endometria. To the best of our knowledge, no studies concerning the effects of mestranol and norethindrone given concurrently on the three-dimensional surface features on the uterine mucosa of the guinea pig have been reported. The purpose of this study was to determine the effect of mestranol and norethindrone on surface ultrastructure of guinea pig uterus by SEM.Seventy eight animals were used in this study. They were allocated into two groups. Group 1 (20 animals) was injected intramuscularly 0.1 ml vegetable oil and served as controls.


Author(s):  
R.P. Apkarian ◽  
J.S. Sanfilippo

The synthetic androgen danazol, is an isoxazol derivative of ethisterone. It is utilized in the treatment of endometriosis, fibrocystic breast disease, and has a potential use as a contraceptive. A study was designed to evaluate the ultrastructural changes associated with danazol therapy in a rat model. The preliminary investigation of the distal segment of the rat uterine horn was undertaken as part of a larger study intended to elucidate the effects of danazol on the female reproductive tract.Cross-sections (2-3 mm in length) of the distal segment of the uterine horn from sixteen Sprague-Dawley rats were prepared for SEM. Ten rats in estrus served as controls and six danazol treated rats were noted to have alterations of the estrus cycle i.e. a lag in cycle phase or noncycling patterns. Specimens were fixed in 3% glutaraldehyde in 0.05M phosphate buffer containing CaCl2 at pH 7.0-7.4 and chilled to 4°C. After a brief wash in distilled water, specimens were passed through a graded series of ethanol, critical point dryed in CO2 from absolute ethanol, and coated with 6nm Au. Observations were made with an IS1-40 SEM operated at 15kV.


Author(s):  
Lawrence M. Roth

The female reproductive tract may be the site of a wide variety of benign and malignant tumors, as well as non-neoplastic tumor-like conditions, most of which can be diagnosed by light microscopic examination including special stains and more recently immunoperoxidase techniques. Nevertheless there are situations where ultrastructural examination can contribute substantially to an accurate and specific diagnosis. It is my opinion that electron microscopy can be of greatest benefit and is most cost effective when applied in conjunction with other methodologies. Thus, I have developed an approach which has proved useful for me and may have benefit for others. In cases where it is deemed of potential value, glutaraldehyde-fixed material is obtained at the time of frozen section or otherwise at operation. Coordination with the gynecologic oncologist is required in the latter situation. This material is processed and blocked and is available if a future need arises.


1966 ◽  
Vol 25 (2) ◽  
pp. 406-409 ◽  
Author(s):  
G. A. Schul ◽  
C. W. Foley ◽  
C. D. Heinze ◽  
R. E. Erb ◽  
R. B. Harrington

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