Sperm Nuclear Decondensation Induction Capacity of In Vitro and In Vivo Matured Canine Oocytes
Article first published online: 24 DEC 2012
© 2012 Blackwell Verlag GmbH
Reproduction in Domestic Animals
Special Issue: Canine and Feline Reproduction VII: Reproductive Biology and Medicine of Domestic and Exotic Carnivores. Proceedings of the 7th Quadrennial International Symposium on Canine and Feline Reproduction. Whistler, Canada. 26-29 July 2012.
Volume 47, Issue Supplement s6, pages 98–101, December 2012
How to Cite
De los Reyes, M., Palomino, J., Parraguez, V. and Vergara, J. (2012), Sperm Nuclear Decondensation Induction Capacity of In Vitro and In Vivo Matured Canine Oocytes. Reproduction in Domestic Animals, 47: 98–101. doi: 10.1111/rda.12013
- Issue published online: 24 DEC 2012
- Article first published online: 24 DEC 2012
- Manuscript Accepted: 20 JUN 2012
- Manuscript Received: 30 MAY 2012
- FONDECYT. Grant Number: 1110265
The objectives of this study were to evaluate the sperm nuclear decondensation capacity of ovulated and in vitro-matured (IVM) canine oocytes during different culture times and correlate this decondensation ability with the state of oocyte nuclear maturation in vitro and in vivo. Fresh ejaculates from three dogs were used for in vitro fertilization (IVF). Dog spermatozoa were cocultured with ovulated or IVM oocytes after each culture period (0, 48, 72 and 96 h) for 24 h. The nuclear stage of the oocytes and the appearance of the sperm nucleus were determined, and data were analysed with a chi-square test. The rates of decondensation and meiotic development in IVM oocytes increased up to 72 h of culture. In contrast, almost all in vivo-matured oocytes showed MII nuclear stage and sperm chromatin decondensation. The percentages of oocytes at MII stage were much lower (p < 0.05) in all IVM groups compared with ovulated oocytes; the rate of sperm chromatin decondensation was higher in ovulated oocytes than in those matured in vitro. Thus, IVM canine oocytes are able to decondense the sperm chromatin during IVF, and this ability increases with time. Nevertheless, sperm chromatin decondensation is less efficient than in ovulated oocytes and may not be completely synchronized with nuclear development as it occurs in vivo.