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DNA repair in oocytes and early embryos
Koubovská, Markéta ; Ďuríček, Tomáš (advisor) ; Macůrek, Libor (referee)
Our diploma thesis focused on the effect of hormonal stimulation on DNA integrity of mammals' oocytes. Later, we also focused on its effect on DNA integrity on mammals' embryos and their developmental potential. Maintaining DNA integrity in germ cells is essential for their quality during fertilization and further development. DNA integrity is disrupted by different types of damage, especially by generating DNA double-strand breaks. We examined the DNA damage in mouse oocytes and embryos, dependent on the dose of hormonal stimulation by PMSG hormone. Immunofluorescence detection γ-H2AX, marker of DNA double-strand breaks, on immature GV oocytes confirmed our primary hypothesis that increasing hormonal stimulation dose increases the number of DNA double-strand breaks. We performed the same experimental design in old mice, but there was no significant difference between groups as it was between groups in young mice. We observed a slight delay in meiotic maturation in hyperstimulated mice using live-cell microscopy compared to the control. In mature MII oocytes, we detected a 3-fold increase in γ-H2AX fluorescence intensity. This difference disappeared in fertilized zygotes, where all γ-H2AX foci were present only in the male pronucleus in both, control and hyperstimulated groups. In terms of...
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