Influence of seminal plasma PSP-I/PSP-II spermadhesin on pig gamete interaction
The seminal plasma PSP-I/PSP-II spermadhesin is able to preserve, in vitro, the viability of highly extended boar spermatozoa, suggesting it might be used as a suitable ameliorator for the damaging effects of sperm handling, including in vitro fertilization. However, little is known about the ligand capability of PSP-I/PSP-II as regards the zona pellucida (ZP) or its possible role in gamete interaction. The present study evaluated the effect of the presence of PSP-I/PSP-II (1.5 mg/ml) during in vitro oocyte maturation and also during co-incubation of frozen-thawed boar spermatozoa with either immature (IM) or in vitro matured (IVM) oocytes, either enclosed by cumulus cells or denuded. Exposure of the gametes to the heterodimer during in vitro gamete co-incubation showed a significant blocking effect of sperm penetration rates and a decreased number of spermatozoa per oocyte in both IM and IVM denuded oocytes. Such an effect was not present in cumulus-enclosed oocytes, suggesting the effect could be mediated by exposed ZP receptors. In addition, when PSP-I/PSP-II was added to the IVM medium, oocyte maturation rates were significantly reduced. In conclusion, the results suggest that PSP-I/PSP-II, when present in vitro, blocks sperm–ZP binding.(Received June 6 2004)
(Accepted January 25 2005)
Key Words: Gametes; IVF; Pig; PSP-I/PSP-II; Seminal plasma.
c1 Correspondence to: J.M. Vázquez, Departamento de Medicina y Cirugía Animal, Facultad de Veterinaria, Universidad de Murcia, 30071 Murcia, Spain. Tel: +34 968 364736. Fax: +34 968 367069. e-mail: firstname.lastname@example.org