In vitro development and cell allocation after aggregation of syngeneic wild type and fluorescence-expressing bovine cloned embryos
Koerich Vieira, FabianoForell, FabianaPereira da Costa Gerger, RenatoHenrique de Aguiar, LuísFeltrin, CristianoGaudencio Neto, SaulEnrique Méndez Calderón, Carlosde Sá Carneiro, IgornaabianaabianaabianaabianaUrio, MonicaMaciel da Costa, UbirajaraRelly Bertolini, LucianaVieira Meirelles, FlávioBertolini, Marcelo
Background: The in vitro production (IVP) of embryos by in vitro fertilization or cloning procedures has been known to cause epigenetic changes in the conceptus that in turn are associated with abnormalities in pre- and postnatal development. Handmade cloning (HMC) procedures and the culture of zona-free embryos in individual microwells provide excellent tools for studies in developmental biology, since embryo development and cell allocation patterns can be evaluated under a wide range of embryo reconstruction arrangements and in in vitro embryo culture conditions. As disturbances in embryonic cell allocation after in vitro embryo manipulations and unusual in vivo conditions during the fi rst third of pregnancy appear to be associated with large offspring, embryo aggregation procedures may allow a compensation for epigenetic defects between aggregated embryos or even may infl uence more favorable cell allocation in embryonic lineages, favoring subsequent development. Thus, the aim of this study was to evaluate in vitro embryo developmental potential and the pattern of cell allocation in blastocysts developed after the aggregation of handmade cloned embryos produced using syngeneic wild type and/or transgenic somatic cells.Materials, Methods & Results: In vitro-matured bovine cumulus-oocyte complexes (COC) were manually bisected after cumulus and zona pellucida removal; then
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