MATERNAL DETERMINANTS OF OOCYTE AND EMBRYO QUALITY release_lkokbb2r5zbc5pxgedcqit325m

Abstract

Oocyte quality plays a critical role in establishment of pregnancies, embryo development, implantation and the health of offspring. The oocyte provides maternal factors necessary for the initial development of its embryo during the period of transcriptional silence. Despite the consistent increase in number of couples seeking assisted reproductive treatments, oocyte quality still remains as an obstacle in successful fertility treatments and the mechanisms governing the quality of oocyte are poorly understood. Among various factors that may potentially affect the quality of oocyte, the acquisition of oocyte developmental competence seems to mainly occur during the final stage of oocyte maturation. The correct temporal regulation of series of molecular events and the proper exchange of signals with surrounding follicular environment during this critical period will ensure the developmental competence of oocyte and its subsequent embryo. In order to identify molecular factors affecting oocyte quality, I have compared oocytes and cumulus cells of different qualities at a molecular level. I present in this thesis the pathways and molecules that may determine the developmental competence of oocyte as well as candidate molecular markers of oocyte and embryo quality. A cDNA microarray analysis was performed, comparing the transcriptomes of rhesus monkey MII oocytes of different qualities, high quality VVM oocytes and poor quality IVM oocytes. A small set of 59 mRNAs was identified as differentially expressed between the two types of oocytes. These mRNAs are involved in steroid metabolism, cell-cell interactions, cellular homeostasis, cell adhesion, mRNA stability and translation. In addition, the overexpression of several imprinted genes in IVM oocytes were detected, indicating a possible loss of correct epigenetic programming during IVM. These results indicate that normal oocyte-somatic cell interactions may be disrupted during IVM and the interruptions of these interactions during the final phase of oocyte maturation m [...]
In text/plain format

Archived Files and Locations