CORTICAL REACTION: KINETICS DIFFERENCES BETWEEN OOCYTES MATURED IN VIVO AND IN VITRO DURING CORTICAL REACTION

CAPPA, ANDREA I.; DE BLAS, GERARDO; DE PAOLA, M. MATILDE; MAYORGA, LUIS S.; MICHAUT, MARCELA A.

Maipú, Mendoza

Congreso; Sociedad de Biologia de Cuyo; 2013

Sociedad de Biologia de Cuyo

Oocyte cortical reaction is a fundamental process which prevents polyspermy ensuring embryo development. In vitro- matured oocytes are used in assisted reproduction, however it is unknown how in vitro maturation affects the oocyte physiology. In this study, we compared the kinetic of cortical reaction between ovulated and in vitro-matured mouse oocytes during cortical reaction. Immature oocytes were collected, after hormonal stimulation (PMSG) from ovaries and in vitro-matured in GIVF media during 15h. Ovulated oocytes were collected, after hormonal stimulation (PMSG-hCG) from ampulla. Cortical reaction was parthenogenetically stimulated in both cell types with SrCl2 in presence of LCA-FITC, which labels cortical granules content. Images were taken every minute during 1h in a Nikon´s ECLIPSE TE300 Inverted Microscope coupled to a led illumination system. Preliminary findings show that cortical reaction is gradual and simultaneous in ovulated oocytes but is abrupt and asynchronous in in vitro-matured oocytes. Our results show for first time the dynamic of cortical reaction in real time and suggest that in vitro maturation affect the kinetic of cortical reaction.