In vitro parthenogenesis of mouse oocytes under several experimental conditions.

MARTINI AC; FIOL DE CUNEO M; RUIZ RD; PONCE AA; LACUARA JL

Zygote

Cambridge University Press

Lugar: Cambridge - UK; Año: 2000 vol. 8 p. 45 - 49

  Although the in vitro fertilization index is a commonly employed parameter to evaluate sperm functional activity, little attention has been given to the occurrence of parthenogenesis. The purpose of this study was to evaluate at 6 h or 22 h incubation: a) the cleavage-related events that occur in in vitro incubated mouse oocytes, in absence (parthenogenesis) or in presence of homologous spermatozoa; b) the effect of mineral oil, commonly used in in vitro fertilization assays, c) the effect of piroxicam, a prostaglandin synthesis inhibitor on the parthenogenetic rate, and d) the influence upon parthenogenesis of spontaneous loss of the cumulus-oophorus coat during incubation. Under the experimental conditions here employed, there existed parthenogenetic activation and activation due to fertilization. Both increased in a time dependent manner. The mineral oil enhanced the parthenogenetic rate at 22 h incubation. However, it did not have any effect when the oocytes were inseminated. Since we can not discriminate how much of this activation is due to fertilization and how much is due to parthenogenesis we must be very careful with this comparison. Piroxicam 10-8 M did not show any effect on the mouse oocyte parthenogenetic rate neither at 6 h nor at 22 h incubation. Our results suggest that the oocyte susceptibility to spontaneous parthenogenetic activation may be modified by the presence of the cumulus and corona radiata cells. In conclusion, we consider that further rigorous studies on these influences are necessary in order to confer more reliability to the results.