Only a subpopulation of mouse sperm displays a rapid increase in intracellular calcium during capacitation
Mammalian sperm must undergo a functionally defined process called capacitation to be able to fertilize oocytes. They become capacitated in vivo by interacting with the female reproductive tract or in vitro in a defined capacitation medium that contains bovine serum albumin, calcium (Ca2+), and bica...
| Autores: | , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/85368 |
| Acceso en línea: | http://hdl.handle.net/11336/85368 |
| Access Level: | acceso abierto |
| Palabra clave: | CALCIUM CAPACITATION CATSPER SPERM https://purl.org/becyt/ford/1.6 https://purl.org/becyt/ford/1 |
| Sumario: | Mammalian sperm must undergo a functionally defined process called capacitation to be able to fertilize oocytes. They become capacitated in vivo by interacting with the female reproductive tract or in vitro in a defined capacitation medium that contains bovine serum albumin, calcium (Ca2+), and bicarbonate (HCO3 −). In this work, sperm were double stained with propidium iodide and the Ca2+ dye Fluo-4 AM and analyzed by flow cytometry to determine changes in intracellular Ca2+ concentration ([Ca2+]i) in individual live sperm. An increase in [Ca2+]i was observed in a subpopulation of capacitated live sperm when compared with noncapacitated ones. Sperm exposed to the capacitating medium displayed a rapid increase in [Ca2+]i within 1 min of incubation, which remained sustained for 90 min. These rise in [Ca2+]i after 90 min of incubation in the capacitating medium was evidenced by an increase in the normalized median fluorescence intensity. This increase was dependent on the presence of extracellular Ca2+ and, at least in part, reflected the contribution of a new subpopulation of sperm with higher [Ca2+]i. In addition, it was determined that the capacitation-associated [Ca2+]i increase was dependent of CatSper channels, as sperm derived from CatSper knockout (CatSper KO) or incubated in the presence of CatSper inhibitors failed to increase [Ca2+]i. Surprisingly, a minimum increase in [Ca2+]i was also observed in CatSper KO sperm suggesting the existence of other Ca2+ transport systems. Altogether, these results indicate that a subpopulation of sperm increases [Ca2+]i very rapidly during capacitation mainly due to a CatSper-mediated influx of extracellular Ca2+. |
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