O-173 Cellular and developmental damage from oocyte cryopreservation

Abstract Compared to somatic or sperm cells, mammalian oocytes are much more sensitive cryopreservation mainly because of the large volume, cytoskeleton, and presence zona pellucida. Connections with surrounding cumulus cells also challenging preserve in immature oocytes. Besides genetic epigenetic information enclosed nucleus, contain organelles cytoplasmic factors that necessary for early embryo development. Therefore, exposure cryoprotectant freezing temperatures can easily damage oocyte’s complex cellular structure developmental competence, which leads poor success fertilization, lower quality, reduced pregnancy rates. Using domestic cat as a model, our laboratory has studied damages cumulus-oocyte complexes (immature oocytes) occurring at each step process. Specifically, this included impact cryoprotectants on microtubules, effect osmotic changes overall structures, well sensitivity nuclear chromatin patterns temperatures. Based those findings, it been possible design mitigating solutions like customized ultra-rapid vitrification protocols, Laser-warming methods, post-warming reanimations. New horizons have explored move away from issues limitations related cryopreservation. Approaches storage long-term non-freezing currently being developed based encouraging data generated preliminary studies. For instance, incorporation trehalose into oocyte followed by microwave-assisted dehydration allow remove enough water while creating protective glass compatible survival Interestingly, transcriptomic proteomic studies already shown stresses induced versus different may be easier overcome.