title: Oocyte vitrification modifies nucleolar remodeling and zygote kinetics-a sibling study.
abstract: OBJECTIVE
  Oocyte vitrification does not affect embryo quality after oocyte warming, making this method effective in the preservation of female fertility. Morphokinetic parameters can be used to predict the competence of an embryo produced from fresh oocytes. Our aim was to study the effect of oocyte vitrification on zygote-embryo kinetics (pl).
  
  
  METHODS
  The embryo-kinetics of fresh and sibling vitrified/warmed oocytes were compared to determine the consequences of oocyte preservation on the timing of embryo development. A 44-hours time-lapse analysis, from the time of ICSI (t0), of 179 fertilized fresh oocytes was compared to 168 fertilized sibling vitrified/warmed oocytes.
  
  
  RESULTS
  Oocyte vitrification accelerated pronuclear disappearance, one-cell stage timing and modified nucleoli activity by increasing their number and decreasing their diameter at the zygote stage. In contrast, embryo kinetics during cleavage were similar to those observed for fresh sibling oocytes based on the parameters examined in this study.
  
  
  CONCLUSIONS
  At the zygote stage, oocyte vitrification induces changes in pronuclei stability, probably due to pronuclei envelop instability as well as modifications in nucleoli functionality. Therefore, the predictive morphokinetic parameters on embryo competence found from fresh oocytes must be revised when applied on embryos from vitrified/warmed oocytes.
authors.affiliation: Unità Di Medicina della Riproduzione - Istituto HERA, via Barriera del Bosco n. 51/53, 95030, Sant'Agata Li Battiati, Catania, Italy, s.chamayou@yahoo.fr.
authors.forename: S
authors.initials: S
authors.lastname: Chamayou
authors.forename: S
authors.initials: S
authors.lastname: Romano
authors.forename: C
authors.initials: C
authors.lastname: Alecci
authors.forename: G
authors.initials: G
authors.lastname: Storaci
authors.forename: C
authors.initials: C
authors.lastname: Ragolia
authors.forename: A
authors.initials: A
authors.lastname: Palagiano
authors.forename: A
authors.initials: A
authors.lastname: Guglielmino
mesh_terms: D000328:Adult; D002466:Cell Nucleolus / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D009865:Oocytes / Q000254:growth & development*; D011247:Pregnancy; D035781:Siblings; D058989:Vitrification; D015053:Zygote / Q000254:growth & development*