Oocyte in vitro maturation after controlled ovarian stimulation

Abstract

During controlled ovarian stimulation (COS), several follicles are recruited and resume meiosis. Nevertheless, some of them do not reach the stage of metaphase II (MII) and are discarded. In these cases, the oocyte in vitro maturation (IVM) after COS may be an important strategy to recover the unmatured oocytes, especially in cases of poor ovarian reserve and to preserve fertility when COS may be a risk factor due to physiological conditions such as cancer and high risk of hyperstimulation syndrome development. In this context, this project aims to develop new insights of oocyte recovery after COS. To do this, immature oocytes [germinal vesicles (GV) and metaphase I (MI)] will be in vitro matured using two different media, the CAPA-IVM and GH-IVM. The maturation rate will be evaluated throw oocytes morphology (zona pellucida integrity and ooplasm) and first polar body extrusion. In addition, mitochondrial and chromatin activity, mitotic spindle formation, protein content and expression of important genes related to oocyte competence, maturation and early embryo development will be evaluated. In addition, the miRNAs and proteins released by the oocyte during the maturation period in the IVM medium will be identified. This project brings IVM as a strategy to recover immature oocytes that would be discarded after COS and thus improve the number of viable oocytes from patients undergoing fertility preservation, besides assisting patients diagnosed with polycystic ovarian syndrome, poor reserve and poor hormonal responder. (AU)