Oocyte cryopreservation is an important technique in the role of infertility treatment and fertility preservation. It has less ethical implications than embryo cryopreservation as one may discard surplus oocytes, what is not possible with embryos. In order to increase the number of retrieved oocytes patients shall be submitted to controlled ovarian hyperstimulation (COH) which represents higher costs and eventually higher risks in cases of oncologic patients with estrogen dependent tumors. Thus the retrieval of immature oocytes followed by in vitro maturation, pre or post gamete cryopreservation, has been pointed as an alternative option to minimize costs and risks. However some studies using bovine models have been presented indicating that oocyte cryopresevation may impair fertilization and embryo development by interfering in mRNA stocks. Changes in the lipid composition of the medium applied on bovine embryo culture seem to interfere on embryo development, probably by modulating cells cryotolerance depending on freezing medium composition. Considering the importance of the vitrification procedure and in vitro maturation on clinical practice the objective of this study is to evaluate the effect of vitrification on the gene expression of oocyte quality markers and also evaluate the effect of phospholipid supplementation on culture medium and/or vitrification medium by analyzing the impact of this supplementation on gene expression and embryo development indexes in order to increase cryotolerance and oocyte viability after cryopreservation.
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