BOR - Papers in Press, published online ahead of print
May 5, 2004.
Biol Reprod 2004, 10.1095/biolreprod.104.028613
BIOLOGY OF REPRODUCTION 71, 790796 (2004)
DOI: 10.1095/biolreprod.104.028613
© 2004 by the Society for the Study of Reproduction, Inc.
Role of Fas-Mediated Apoptosis and Follicle-Stimulating Hormone on the Developmental Capacity of Bovine Cumulus Oocyte Complexes In Vitro1
Francisco J. Rubio Pomar3,
Bernard A.J. Roelen2,3,
Karin A. Slot4,
Helena T.A. van Tol3,
Ben Colenbrander3, and
Katja J. Teerds5
Department of Farm Animal Health3
Department of Cell Biology and Biochemistry,4 Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
Department of Animal Sciences,5 Human and Animal Physiology Group, Wageningen University, Wageningen, The Netherlands
Follicular atresia is believed to be largely regulated by apoptosis. To further understand how apoptosis can affect cumulus cells and oocytes we have evaluated the incidence and regulation of apoptosis affecting bovine cumulus oocyte complexes in vitro. Expression of components of the Fas signaling pathway was studied in both oocytes and cumulus cells by polymerase chain reaction after reverse transcription, immunoblotting, and indirect immunofluorescence. Furthermore, the Fas signaling pathway was activated in cumulus oocyte complexes with an agonistic anti-Fas antibody during in vitro maturation in the presence or absence of FSH. Viability and incidence of apoptosis in cumulus cells were evaluated by assessing membrane integrity and nuclear morphology. Oocyte nuclear maturation was also analyzed, as well as cleavage rates, blastocyst formation rates, and blastocyst quality, following in vitro fertilization. Fas mRNA and protein were expressed both in oocytes and cumulus cells. FasL protein was found in cumulus cells but could not be detected in oocytes, despite its mRNA expression. Both activation of the Fas pathway and presence of FSH during in vitro maturation increased the incidence of apoptosis in cumulus cells, affecting predominantly the middle and peripheral regions of the cumulus. The observed increase, however, had no effect on the developmental competence of the oocytes.
1 This work was supported in part by funds from Holland Genetics.
2 Correspondence: Bernard A.J. Roelen, Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584 CL Utrecht. FAX: 31 030 253 4811; b.a.j.roelen{at}vet.uu.nl
Copyright © 2004 by the Society for the Study of Reproduction.