title: Morphological alterations and DNA fragmentation in oocytes from primordial and primary follicles after freezing-thawing of ovarian cortex in sheep.
abstract: OBJECTIVE
  To evaluate DNA fragmentation in the oocyte of primordial and primary follicles and morphology of these follicles after freezing and thawing of ovarian cortex in sheep using two freezing protocols.
  
  
  METHODS
  Fragmentation of DNA was evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) technique.
  
  
  METHODS
  Fertility clinic in a large university hospital.
  
  
  METHODS
  Five- to 6-month-old lambs.
  
  
  METHODS
  Two-millimeter-thick slices of hemi-ovary cortex were prepared.
  
  
  METHODS
  Histological structure and DNA fragmentation.
  
  
  RESULTS
  In the frozen fragments, the percentage of morphologically normal follicles was significantly lower for both protocols compared with the case of the control group of fresh fragments. There was no significant difference between the two types of freezing protocols (60.4% +/- 13.2% vs. 68.4% +/- 13.7%). However, the distribution of abnormalities (nucleus, cytoplasm, and nucleus and cytoplasm) was dissimilar. The results of the TUNEL technique for the three groups showed no significant difference, but the percentage of the TUNEL-positive follicles was slightly lower for the frozen fragments for both protocols with respect to the control group.
  
  
  CONCLUSIONS
  The freezing and thawing process of the ovarian cortex does not induce fragmentation of the DNA on the oocyte of primary and primordial follicles.
authors.affiliation: Laboratoire de Zootechnie, Ecole Nationale Vétérinaire de Lyon, Marcy l'Etoile, France. b.demerci@vet-lyon.fr
authors.forename: Banu
authors.initials: B
authors.lastname: Demirci
authors.forename: Bruno
authors.initials: B
authors.lastname: Salle
authors.forename: Lucien
authors.initials: L
authors.lastname: Frappart
authors.forename: Michel
authors.initials: M
authors.lastname: Franck
authors.forename: Jean François
authors.initials: JF
authors.lastname: Guerin
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Lornage
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D053938:DNA Fragmentation / Q000502:physiology*; D005260:Female; D006651:Histocytochemistry / Q000662:veterinary; D020287:In Situ Nick-End Labeling / Q000662:veterinary; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D006080:Ovarian Follicle / Q000166:cytology / Q000502:physiology*; D012756:Sheep / Q000502:physiology*; D018709:Statistics, Nonparametric