Project description:In vitro maturation (IVM) of the oocytes is a routine method in bovine embryo production. The competence of bovine oocytes to develop into embryo after IVM and in vitro fertilization (IVF) is lower as compared to in vivo preovulatory oocytes. Cumulus cells (CC) that enclose an oocyte are involved in the acquisition of oocyte quality during maturation. Using transcriptomic approach we compared cumulus cells gene expression during IVM with that in vivo preovulatory period. Global transcriptional profiling was performed using cumulus cells collected from mature bovine oocytes (metaphase-II stage) after maturation performed either in vivo or in vitro. In vivo matured cumulus cells were collected from ovulatory follicles of Montbeliard adult cows by ovum pick-up in vivo (OPU, n=4). In vitro matured cumulus cells were recovered from the oocytes after 22h of in vitro culture of cumulus-oocyte complexes (50 COC per experiment) from 2-6 mm ovarian follicles of adult cows (MIV, n=4). Gene expression analysis was carried out between in vivo and in vitro matured cumulus representing a total of 8 slides (dye swap protocol)
Project description:In vitro maturation (IVM) of the oocytes is a routine method in bovine embryo production. The competence of bovine oocytes to develop into embryo after IVM and in vitro fertilization (IVF) is lower as compared to in vivo preovulatory oocytes. Cumulus cells (CC) that enclose an oocyte are involved in the acquisition of oocyte quality during maturation. Using transcriptomic approach we compared cumulus cells gene expression during IVM with that in vivo preovulatory period.
Project description:In cattle, almost all fully grown vesicle stage oocytes (GV) have the ability to resume meisos, develop to Metaphase II stage (MII), support fertilization and progress through the early embryonic cycles in vitro. Yet without intensive selection, the majority fail to develop to the blastocyst stage. Using the Affymetrix Bovine Genome Array, global mRNA expression analysis of immature (GV) and in vitro matured (IVM) bovine oocytes was carried out to characterize the transcriptome of the bovine oocyte and to identify the key pathways associated with oocyte meiotic maturation and developmental potential. Immature and in vitro matured bovine oocytes were collected for RNA extraction and hybridization on Affymetrix GeneChip Bovine Genome array. Careful removal of cumulus and selection of oocytes was carried out under the stereo microscope in order to examine the actual cumulus-free temporal oocyte gene expression profiles. Immature oocytes at time 0 h and in vitro matured oocytes at 24 h were collected for analysis.
Project description:Maturation of oocytes under in-vitro conditions (IVM) results in impaired developmental competence compared to oocytes matured in-vivo. Oocytes are closely coupled to their cumulus complex (COC) with a bidirectional exchange of metabolites. Therefore, elucidation of aberrations in cumulus metabolism in-vitro is crucial for a better mimicking of physiological maturation conditions. The aim of this study was the analysis of the equine cumulus cells proteome of single cumulus complexes of metaphase II oocytes matured either under in-vivo (n=8) or in-vitro (n=7) conditions. For in-vivo COC collection mares were slaughtered 30 hours after injection and cumulus complexes from the dominant follicle were harvested for analysis. For in-vitro maturation COCs were recovered from mares out of oestrous and matured for 30 hours in-vitro. COCs were separated in cumulus complexes and oocytes, and only cumulus of successfully matured oocytes was analyzed for this study. All cumulus samples were washed, snap frozen and stored in liquid nitrogen until preparation for analysis.
Project description:The oocyte forms a complex with their somatic cumulus cells within the follicle throughout the preovulatory maturation steps. Cumulus cells support their oocyte not only through mechanical protection but also with a close bidirectional exchange of metabolites. Analysis of the oocytes cumulus gives the opportunity to explore non-invasively oocytal well-being and quality. In vitro maturation (IVM) is the first rate-limiting step in in vitro embryo production. Analysis of protein expression in cumulus cells around this critical step helps to explore the impact of maturation conditions and to examine an influence on maturational competence of the oocyte. The goal of this study was the comparison of the cumulus proteome of oocytes with and without maturational competence matured under in vivo and in vitro conditions. Therefore twenty cumulus samples corresponding to single oocytes were analysed. Half of the samples were matured in vivo and the other half in vitro. For each maturation group, cumulus from oocytes matured successfully (SM; n=5) and failed to mature (FM; n=5) were analysed.
Project description:Cumulus cells, surrounding the oocyte, play a key role in the acquisition of oocyte competence to be fertilized and to sustain early embryo development. Cumulus cells contribute to oocyte development by metabolizing energy substrates such as glutathione that may protect the oocyte from oxidative stress damages. The aim of our study was to compare transcriptomics profiles of cumulus enclosed (CEO) and cumulus denuded (CDO) oocytes after in vitro maturation. Global transcriptional profiling was performed using cumulus enclosed and cumulus denuded oocytes after in vitro maturation. Matured oocytes were obtained after 22h of maturation with (CEO) or without (CDO) cumulus cells and four replicates of 25 oocytes were collected for RNA extraction. Gene expression analysis was performed by comparing CDO versus CEO oocytes that represents a total of 8 slides using a dye swap hybridisation protocol.
Project description:In vitro maturation (IVM) of equine oocytes results in a reduced developmental capacity compared to in vivo matured oocytes. Cumulus cells mirror oocytal well-being through close bidirectional communication. After maturation, the cumulus complex is not required anymore. Therefore, these cells are a unique noninvasive source to investigate metabolism during this crucial developmental phase. This study analyzed the “Cumulome” (metabolome and proteome of cumulus cells) with different developmental potential: Not matured (NM; n=18), Cleaved (CL; n=15) and Blastocyst (BL; n=19).
Project description:Somatic cells surrounding the oocyte were sampled at the following stages: developmentally incompetent or poorly competent prophase I oocytes (NC1 oocytes), developmentally competent prophase I oocytes (C1 oocytes), and developmentally competent metaphase II oocytes (C2 oocytes). NC1 cumulus cells (CC) were sampled from immature calf oocytes, C1 samples from immature cow oocytes, and C2 samples from in vivo matured cow oocytes. Global transcriptional profiling was performed using cumulus cells collected from bovine ovarian follicles during in vivo oocyte developmental competence acquisition. Cumulus cells were collected at 3 stages: early stage follicles (prophase I arrested oocytes, meiotically competent but developmentally incompetent, n=6), late stage follicles (prophase I arrested oocytes, meiotically competent and developmentally competent, n=6) and ovulatory follicles collected by ovum pick-up (OPU) in vivo (metaphase II arrested oocytes, developmentally fully competent, n=5).