Published-Ahead-of-Print June 28, 2006, DOI:10.2164/jandrol.106.000539
Journal of Andrology, Vol. 27, No. 6, November/December 2006
Copyright © American Society of Andrology
DOI: 10.2164/jandrol.106.000539
Immunolocalization and Possible Functional Role of PSP-I/PSP-II Heterodimer in Highly Extended Boar Spermatozoa
IGNACIO CABALLERO*,
JUAN M. VÁZQUEZ*,
EVA M. GARCÍA*,
JORDI ROCA*,
EMILIO A. MARTÍNEZ*,
JUAN J. CALVETE
,
LIBIA SANZ
,
HANS EKWALL
AND
HERIBERTO RODRÍGUEZ-MARTÍNEZ
From the * Department of Medicine and Surgery,
Faculty of Veterinary Medicine, University of Murcia, Murcia, Spain; the
Institute of Biomedicine, C.S.I.C., Valencia,
Spain; and the
Division of Comparative
Reproduction, Faculty of Veterinary Medicine and Animal Science, Swedish
University of Agricultural Sciences (SLU), Uppsala, Sweden
|
Correspondence to: Juan M Vazquez, Departamento de Medicina y Cirugía
Animal, Facultad de Veterinaria, Universidad de Murcia, 30071 Murcia, Spain
(e-mail:
vazquez{at}um.es). |
PSP-I/PSP-II heterodimer is a major protein of boar seminal plasma which is
able to preserve, in vitro, the viability, motility, and mitochondrial
activity of highly extended boar spermatozoa for at least 5 hours. However,
little is known about the binding pattern of the heterodimer to the sperm
plasma membrane and its eventual relation with the maintenance of the sperm
functionality. The present study investigated the effect of exposing highly
extended boar spermatozoa (1 million/mL) to 1.5 mg/mL of PSP-I/PSP-II for 0.5,
5, and 10 hours at 38°C on sperm characteristics and the changes in
PSP-I/PSP-II localization as a result of both the addition of PSP-I/PSP-II to
the extender and the incubation time. Exposure of the spermatozoa to
PSP-I/PSP-II preserved sperm viability, motility, and mitochondrial activity
when compared to nonexposed spermatozoa. This protective effect lasted for 10
hours (P < .05). After immunolabeling of highly extended semen
with rabbit monospecific polyclonal antibody against PSP-I/PSP-II, the
percentage of immunopositive spermatozoa declines over time from 71% (0.5
hours) to 49% (10 hours). However, more than 80% of spermatozoa remained
labeled during the 10-hour incubation period if PSP-I/PSP-II was added.
Scanning electron microscopy revealed 4 different binding patterns. The
heterodimer was mainly localized to the acrosomal area, being redistributed to
the postacrosomal area or lost during in vitro incubation. In conclusion, the
protective effect of the heterodimer appears to be related to its adhesion to
the acrosomal area, and the loss of this protective effect coincides with a
stepwise redistribution of PSP-I/PSP-II during incubation.
Key words: Reproductive tract, semen, sperm, seminal plasma, sperm capacitation
Copyright © 2006 by The American Society of Andrology.