title: Genotoxicity assessment of mouse oocytes by comet assay before vitrification and after warming with three vitrification protocols.
abstract: OBJECTIVE
  To assess the genotoxicity of three oocyte vitrification protocols.
  
  
  METHODS
  Murine assay.
  
  
  METHODS
  Biogenotoxicology research laboratory.
  
  
  METHODS
  CD1 female mice.
  
  
  METHODS
  Three mouse oocyte groups were exposed to three commercialized human oocyte vitrification protocols. Protocols 1 and 2 contained dimethyl sulfoxide and ethylene glycol (EG), and protocol 3 contained EG and 1,2-propanediol (PrOH). DNA damage was first evaluated by comet assay after oocyte exposure to the three different equilibration and vitrification solutions. Comet assay was also performed after full vitrification and warming procedure and compared with a negative control group (oocytes stored in medium culture only) and a positive control group (oocytes exposed to hydrogen peroxide just before comet assay).
  
  
  METHODS
  DNA damage was quantified as Olive tail moment (OTM). Statistical analysis consisted of a Shapiro-Wilk test. Then, median protocol OTM was compared with the negative control group with the Mann-Whitney U test. The difference was considered to be statistically significant if the P value was <.05.
  
  
  RESULTS
  In both parts of our study, protocols 1 and 2 did not induce significant DNA damage, whereas protocol 3 induced statistically higher DNA damage compared with the negative control group.
  
  
  CONCLUSIONS
  Vitrification protocols containing PrOH induced significant DNA damage on mouse oocytes, both before cooling and after warming. Therefore, for the moment, we prefer vitrification techniques without PrOH while we await more studies on PrOH toxicity and long-term evaluation.
authors.affiliation: Biogénotoxicologie, Santée Humaine & Environnement UMR 6116, IMBE, Aix-Marseille Université, FR CNRS 3098, ECCOREV, Marseille, France.
authors.forename: Anais
authors.initials: A
authors.lastname: Berthelot-Ricou
authors.forename: Jeanne
authors.initials: J
authors.lastname: Perrin
authors.forename: Carole
authors.initials: C
authors.lastname: di Giorgio
authors.forename: Michel
authors.initials: M
authors.lastname: de Meo
authors.forename: Alain
authors.initials: A
authors.lastname: Botta
authors.forename: Blandine
authors.initials: B
authors.lastname: Courbiere
mesh_terms: D000818:Animals; D020552:Comet Assay; D003451:Cryoprotective Agents / Q000494:pharmacology; D004249:DNA Damage; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D019855:Ethylene Glycol / Q000494:pharmacology; D005260:Female; D051379:Mice; D009584:Nitrogen / Q000494:pharmacology; D054315:Oocyte Retrieval / Q000379:methods; D009865:Oocytes; D013696:Temperature; D058989:Vitrification; D014867:Water
chemical_list: D003451:Cryoprotective Agents; D014867:Water; D019855:Ethylene Glycol; D009584:Nitrogen; D004121:Dimethyl Sulfoxide
keywords: DNA damage; Oocyte vitrification; comet assay; cryoprotectants; genotoxicity