title: In vitro maturation, apoptotic gene expression and incidence of numerical chromosomal abnormalities following cryotop vitrification of sheep cumulus-oocyte complexes.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effects of cryotop vitrification of sheep cumulus-oocyte complexes (COCs) on oocyte maturation, apoptotic gene expression and incidence of chromosomal abnormalities.
  
  
  METHODS
  Freshly isolated (control group) and vitrified-warmed COCs (cryotop group) were matured in vitro. The expression of pro- and anti-apoptotic genes was investigated by real-time PCR. The incidence of numerical chromosomal abnormalities was evaluated by cytogenetic analysis.
  
  
  RESULTS
  The mean percentage of oocytes in the cryotop and control groups that reached metaphase II was 49.25 +/- 3.01% and 51.94 +/- 2.7% respectively. The expression rates of pro- and anti-apoptotic genes were similar in both groups, whereas the incidence of numerical chromosomal abnormalities was higher in the cryotop group compared to the control group (42.5% vs. 20%, p < 0.05).
  
  
  CONCLUSIONS
  Although cryotop vitrification of COCs did not affect the incidence of oocyte maturation or apoptotic gene expression, significant deficiencies in the maintenance of oocyte chromosomal organization were seen.
authors.affiliation: Department of Anatomy, Faculty of Medical Science, Tarbiat Modares University, Tehran, Iran.
authors.forename: Bita
authors.initials: B
authors.lastname: Ebrahimi
authors.forename: Mojtaba Rezazadeh
authors.initials: MR
authors.lastname: Valojerdi
authors.forename: Poopak
authors.initials: P
authors.lastname: Eftekhari-Yazdi
authors.forename: Hossein
authors.initials: H
authors.lastname: Baharvand
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D002470:Cell Survival; D002869:Chromosome Aberrations / Q000662:veterinary; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology; D054885:Cumulus Cells / Q000166:cytology / Q000187:drug effects; D005260:Female; D005307:Fertilization in Vitro; D015870:Gene Expression / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D009866:Oogenesis / Q000187:drug effects; D012756:Sheep / Q000502:physiology*
chemical_list: D003451:Cryoprotective Agents