title: A phosphodiesterase type-5 inhibitor, sildenafil, induces sperm capacitation and penetration into porcine oocytes in a chemically defined medium.
abstract: The present study was undertaken to determine the effect of a phosphodiesterase (PDE) type-5 (cyclic guanosine monophosphate-specific) inhibitor, sildenafil, on capacitation and penetration of boar spermatozoa in a basic chemically defined medium (adenosine- and theophylline-free PGM-tac4). When ejaculated spermatozoa were cultured for 90 minutes in the absence or presence of sildenafil at 2.5 mM, the inhibitor significantly increased the percentage of capacitated/acrosome-reacted spermatozoa, as a result of the chlortetracycline assay. When fresh spermatozoa were co-cultured with oocytes in the presence of sildenafil at a different concentration (0, 2.5, 25, or 250 μM), higher sildenafil concentrations (25 and 250 μM) significantly resulted in higher sperm penetration rates. When oocytes matured in vitro were co-cultured with spermatozoa in the presence of 25 μM sildenafil or 25 mM caffeine benzoate for 8 hours, the incidence of penetrated oocytes did not differ between two groups, whereas the incidence of monospermic oocytes in penetrated one was significantly higher in the presence of sildenafil. Immunocytochemical analysis reported the presence of PDE type-5 on the acrosome region of boar spermatozoa. These results report that regulation of cyclic guanosine monophosphate-specific PDE type-5 by sildenafil somehow can increase the penetrability of boar spermatozoa in vitro.
authors.affiliation: Department of Animal Science, Okayama University, Okayama, Japan.
authors.forename: Sumire
authors.initials: S
authors.lastname: Ioki
authors.affiliation: Department of Animal Science, Okayama University, Okayama, Japan.
authors.forename: Qing-Shan
authors.initials: QS
authors.lastname: Wu
authors.affiliation: Assisted Reproductive Technology Center, Okayama University, Okayama, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Takayama
authors.affiliation: Assisted Reproductive Technology Center, Okayama University, Okayama, Japan.
authors.forename: Hideyuki H
authors.initials: HH
authors.lastname: Motohashi
authors.affiliation: Department of Animal Science, Okayama University, Okayama, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Wakai
authors.affiliation: Department of Animal Science, Okayama University, Okayama, Japan; Assisted Reproductive Technology Center, Okayama University, Okayama, Japan. Electronic address: hirofun@okayama-u.ac.jp.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Funahashi
mesh_terms: D020101:Acrosome Reaction / Q000187:drug effects; D000818:Animals; D001565:Benzoates / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology; D003470:Culture Media; D004338:Drug Combinations; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods / Q000662:veterinary; D059471:In Vitro Oocyte Maturation Techniques / Q000662:veterinary; D008297:Male; D058986:Phosphodiesterase 5 Inhibitors; D000068677:Sildenafil Citrate / Q000032:analysis / Q000494:pharmacology*; D013075:Sperm Capacitation / Q000187:drug effects*; D013084:Sperm-Ovum Interactions / Q000187:drug effects*; D013094:Spermatozoa / Q000737:chemistry; D013552:Swine
chemical_list: D001565:Benzoates; D003470:Culture Media; D004338:Drug Combinations; D058986:Phosphodiesterase 5 Inhibitors; D002110:Caffeine; D000068677:Sildenafil Citrate; C025741:caffeine, sodium benzoate drug combination
keywords: IVF; Monospermy; Phosphodiesterase type-5 inhibitor; Porcine; Spermatozoa