Combined albumin and bicarbonate induces head-to-head sperm agglutination which physically prevents equine sperm-oviduct binding.
Abstract: In many species, sperm binding to oviduct epithelium is believed to be an essential step in generating a highly fertile capacitated sperm population primed for fertilization. In several mammalian species, this interaction is based on carbohydrate-lectin recognition. D-galactose has previously been characterized as a key molecule that facilitates sperm-oviduct binding in the horse. We used oviduct explant and oviduct apical plasma membrane (APM) assays to investigate the effects of various carbohydrates; glycosaminoglycans; lectins; S-S reductants; and the capacitating factors albumin, Ca(2+) and HCO3(-) on sperm-oviduct binding in the horse. Carbohydrate-specific lectin staining indicated that N-acetylgalactosamine, N-acetylneuraminic acid (sialic acid) and D-mannose or D-glucose were the most abundant carbohydrates on equine oviduct epithelia, whereas D-galactose moieties were not detected. However, in a competitive binding assay, sperm-oviduct binding density was not influenced by any tested carbohydrates, glycosaminoglycans, lectins or D-penicillamine, nor did the glycosaminoglycans induce sperm tail-associated protein tyrosine phosphorylation. Furthermore, N-glycosidase F (PNGase) pretreatment of oviduct explants and APM did not alter sperm-oviduct binding density. By contrast, a combination of the sperm-capacitating factors albumin and HCO3(-) severely reduced (>10-fold) equine sperm-oviduct binding density by inducing rapid head-to-head agglutination, both of which events were independent of Ca(2+) and an elevated pH (7.9). Conversely, neither albumin and HCO3(-) nor any other capacitating factor could induce release of oviduct-bound sperm. In conclusion, a combination of albumin and HCO3(-) markedly induced sperm head-to-head agglutination which physically prevented stallion sperm to bind to oviduct epithelium.
© 2016 Society for Reproduction and Fertility.
Publication Date: 2016-01-11 PubMed ID: 26755687DOI: 10.1530/REP-15-0471Google Scholar: Lookup
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- Journal Article
Summary
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This study investigates how various factors affect the binding of horse sperm to the oviduct, a necessary process for successful fertilization. The researchers found that the combination of the substances albumin and bicarbonate cause horse sperm to clump together, reducing the ability of the sperm to bind to the oviduct.
Background and Objective
- The ability of sperm to bind to the epithelium, or surface cells, of the oviduct is crucial for successful fertilization in many species.
- In some mammals, this interaction relies on a recognition process between carbohydrates and proteins called lectins.
- The study aims to understand how different carbohydrates, proteins, and other factors influence this binding process in horses (equine).
Methods and Approach
- The team used explants, tissues extracted for experimental purposes, and apical plasma membranes (APM) assays derived from the oviduct to observe sperm-oviduct binding.
- They investigated the effects of various carbohydrates, glycosaminoglycans (long unbranched polysaccharides), lectins, S-S reductants, and the capacitating factors albumin, Ca(2+) and HCO3(-). Capacitation refers to the physiological changes sperm undergo to become capable of fertilizing an egg.
- Staining with carbohydrate-specific lectins was employed to determine the composition of the oviduct epithelia.
- A competitive binding assay was performed to measure the effect on the density of sperm-oviduct binding.
Findings
- The most abundant carbohydrates on the oviduct epithelia were N-acetylgalactosamine, N-acetylneuraminic acid (sialic acid), and D-mannose or D-glucose. Surprisingly, D-Galactose, previously characterized as a crucial molecule, was not detected.
- No significant effect on sperm-oviduct binding was observed due to the molecules tested: carbohydrates, glycosaminoglycans, lectins, or D-penicillamine.
- N-glycosidase F (PNGase) pretreatment did not change the density of the binding.
- A significant (>10-fold) reduction in sperm-oviduct binding was seen when albumin and HCO3(-) were present, as they caused the sperm to agglutinate or cluster together. This effect was independent of Ca(2+) and an elevated pH level.
- The combination of albumin and HCO3(-), as well as other capacitating factors, could not induce the release of sperm already bound to the oviduct.
- In conclusion, the research suggests that albumin and HCO3(-) caused a marked increase in sperm head-to-head agglutination, which in turn physically prevented the sperm from binding to the oviduct.
Cite This Article
APA
Leemans B, Gadella BM, Stout TA, Sostaric E, De Schauwer C, Nelis H, Hoogewijs M, Van Soom A.
(2016).
Combined albumin and bicarbonate induces head-to-head sperm agglutination which physically prevents equine sperm-oviduct binding.
Reproduction, 151(4), 313-330.
https://doi.org/10.1530/REP-15-0471 Publication
Researcher Affiliations
- Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands baleeman.leemans@ugent.be.
- Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
- Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
- Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
- Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
- Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
- Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
- Department of ReproductionObstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, BelgiumDepartments of Farm Animal HealthBiochemistry and Cell BiologyEquine SciencesFaculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
MeSH Terms
- Albumins / pharmacology
- Animals
- Bicarbonates / pharmacology
- Buffers
- Female
- Horses
- Male
- Oviducts / drug effects
- Oviducts / metabolism
- Sperm Agglutination / drug effects
- Sperm Capacitation / drug effects
- Sperm Head / drug effects
- Sperm Head / metabolism
Citations
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