Changes in Nucleus and Cytoplast During Oocyte Maturation: Involvement in Embryo Production

Abstract

Embryo production steps either in vivo or in vitro include oocyte meiotic maturation, fertilization and culture processes. Oocyte maturation is the first step for in vivo or in vitro embryo production. Oocyte maturation appears to be a simple step, but it is a very complex process. Maturation of oocytes include several changes at the cytoplasmic and nuclear levels that makes the oocytes able to undergo fertilization, pre-implantation and post-implantation embryo development. Oocyte meiotic maturation in vivo starts after LH hormone surge whereas it starts in vitro upon release of oocyte from the ovarian follicle. Rodent oocyte maturation lasts 15-17hr. whereas that of ruminant oocyte lasts 24hr. Several factors affect on oocytes maturation either in vitro or in vivo and therefore affect development of the resulting embryos. Because of the significance of oocyte maturation stage on further embryonic development, this review aims to discuss the knowledge of oocyte maturation and its effect on further development of embryos in vivo and in vitro.