Efeito de bloqueadores meióticos na maturação e ultraestrutura de oócitos e sua conseqüência na produção de embriões in vitro

Abstract

The aim of this study was test the effect of Cordicepim (CY), an inhibitor of mRNA translation, associate with growth factor (IGF-I), in the presence or absence of Roscovitina (Ros), a mitogen promoting factor blocker. Twelve hours in culture media with CY plus 18 or 24 hours of maturation resulted in an average of 80% of oocytes reaching metaphase II. The blastocyst yield after 12 hours culture media with CY plus 18 hours of maturation without inhibition (32.3%) was similar (P>0.05) to the control group (39.6%). A negative effect of Ros on blastocyst yield was observed when not associated to CY, (16.7% in Ros vs 49% in control group). When the concentration of Ros associated with CY was reduced, the blastocyst yield was lower (8.3%) compared with the control group (36.4%). Transmission electron microscopy evaluation showed characteristics like a mature oocyte but also some characteristics of immature oocyte after 12 hours of inhibition. In conclusion, the temporary exposure of bovine oocytes to CY associated with IGF-I during in vitro maturation allowed an increase in culture time with no effect on cytoplasm ultra-structure and blastocyst yield, associated or not with Roscovitina