title: Intracellular calcium movements of boar spermatozoa during 'in vitro' capacitation and subsequent acrosome exocytosis follow a multiple-storage place, extracellular calcium-dependent model.
abstract: This work analysed intracellular calcium stores of boar spermatozoa subjected to 'in vitro' capacitation (IVC) and subsequent progesterone-induced acrosome exocytosis (IVAE). Intracellular calcium was analysed through two calcium markers with different physico-chemical properties, Fluo-3 and Rhod-5N. Indicative parameters of IVC and IVAE were also evaluated. Fluo-3 was located at both the midpiece and the whole head. Rhod-5N was present at the sperm head. This distribution did not change in any of the assayed conditions. Induction of IVC was concomitant with an increase in both head and midpiece Ca(2+) signals. Additionally, while IVC induction was concurrent with a significant (p < 0.05) increase in sperm membrane permeability, no significant changes were observed in O2 consumption and ATP levels. Incubation of boar spermatozoa in the absence of calcium showed a loss of both Ca(2+) labellings concomitantly with the sperm's inability to achieve IVC. The absence of extracellular calcium also induced a severe decrease in the percentage of spermatozoa exhibiting high mitochondrial membrane potential (hMMP). The IVAE was accompanied by a fast increase in both Ca(2+) signalling in control spermatozoa. These peaks were either not detected or much lessened in the absence of calcium. Remarkably, Fluo-3 marking at the midpiece increased after progesterone addition to sperm cells incubated in a medium without Ca(2+) . The simultaneous addition of progesterone with the calcium chelant EGTA inhibited IVAE, and this was accompanied by a significant (p < 0.05) decrease in the intensity of progesterone Ca(2+) -induced peak, O2 consumption and ATP levels. Our results suggest that boar spermatozoa present different calcium deposits with a dynamic equilibrium among them and with the extracellular environment. Additionally, the modulation role of the intracellular calcium in spermatozoa function seems to rely on its precise localization in boar spermatozoa.
authors.affiliation: Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Autonomous University of Barcelona, Bellaterra (Cerdanyola del Vallès), Spain.|Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Oxford, UK.
authors.forename: M
authors.identifier: http://orcid.org/0000-0002-2209-340X
authors.initials: M
authors.lastname: Yeste
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Fernández-Novell
authors.affiliation: Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Autonomous University of Barcelona, Bellaterra (Cerdanyola del Vallès), Spain.
authors.forename: L
authors.initials: L
authors.lastname: Ramió-Lluch
authors.affiliation: Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Autonomous University of Barcelona, Bellaterra (Cerdanyola del Vallès), Spain.
authors.forename: E
authors.initials: E
authors.lastname: Estrada
authors.affiliation: Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Autonomous University of Barcelona, Bellaterra (Cerdanyola del Vallès), Spain.
authors.forename: L G
authors.initials: LG
authors.lastname: Rocha
authors.affiliation: Department of Biochemistry and Molecular and Cell Biology, IUCA, School of Veterinary Medicine, University of Zaragoza-IUCA, Zaragoza, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Cebrián-Pérez
authors.affiliation: Department of Biochemistry and Molecular and Cell Biology, IUCA, School of Veterinary Medicine, University of Zaragoza-IUCA, Zaragoza, Spain.
authors.forename: T
authors.initials: T
authors.lastname: Muiño-Blanco
authors.affiliation: Institute of Biochemistry and Microbiology and Institute of Animal Science, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: I I
authors.initials: II
authors.lastname: Concha
authors.affiliation: Institute of Biochemistry and Microbiology and Institute of Animal Science, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: A
authors.initials: A
authors.lastname: Ramírez
authors.affiliation: Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Autonomous University of Barcelona, Bellaterra (Cerdanyola del Vallès), Spain.
authors.forename: J E
authors.initials: JE
authors.lastname: Rodríguez-Gil
mesh_terms: D020101:Acrosome Reaction; D000255:Adenosine Triphosphate / Q000378:metabolism; D000814:Aniline Compounds; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004533:Egtazic Acid; D005089:Exocytosis; D008297:Male; D008560:Membrane Fluidity; D053078:Membrane Potential, Mitochondrial; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism; D012235:Rhodamines; D013075:Sperm Capacitation; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism*; D013552:Swine / Q000378:metabolism*; D014966:Xanthenes
chemical_list: D000814:Aniline Compounds; C574804:Rhod-5N; D012235:Rhodamines; D014966:Xanthenes; C059715:Fluo-3; D004533:Egtazic Acid; D000255:Adenosine Triphosphate; D010100:Oxygen; D002118:Calcium
keywords: acrosome exocytosis; boar spermatozoa; calcium; capacitation; motility