title: Strategies for using the sheep ovarian cortex as a model in reproductive medicine.
abstract: OBJECTIVE
  To evaluate and compare the distribution and density of primordial follicles within a whole sheep ovary and to gain insight into how to overcome the impact of natural follicular heterogeneity on the experimental results.
  
  
  METHODS
  Histological study.
  
  
  METHODS
  Academic research center.
  
  
  METHODS
  Five- to nine-month-old ewes.
  
  
  METHODS
  Freshly sampled whole sheep ovaries were collected and prepared for histological analysis.
  
  
  METHODS
  The follicular densities and distributions were determined for hematoxylin and eosin sections. A mathematical model was derived based on the follicle counts and Monte-Carlo simulations.
  
  
  RESULTS
  Heterogeneous distributions and densities of primordial follicles were identified 1) for distinct areas of the same ovarian cortex, 2) between the ovaries of the same animal and 3) across different ewes. A mathematical model based on the analysis of 37,153 primordial follicles from 8 different ovaries facilitated the estimation of the number of cortical biopsies and sections that had to be analyzed to overcome such heterogeneity.
  
  
  CONCLUSIONS
  The influence of physiological follicular heterogeneity on experimental and clinical results can be overcome when a definite number of cortical pieces and sections are taken into consideration.
authors.affiliation: Laboratory of Tumor and Developmental Biology, GIGA-R, University of Liège, Tour de Pathologie (B23), Sart Tilman, Liège, Belgium.
authors.forename: Maïté
authors.initials: M
authors.lastname: Fransolet
authors.affiliation: Laboratory of Tumor and Developmental Biology, GIGA-R, University of Liège, Tour de Pathologie (B23), Sart Tilman, Liège, Belgium.
authors.forename: Soraya
authors.initials: S
authors.lastname: Labied
authors.affiliation: Laboratory of Tumor and Developmental Biology, GIGA-R, University of Liège, Tour de Pathologie (B23), Sart Tilman, Liège, Belgium.
authors.forename: Laurie
authors.initials: L
authors.lastname: Henry
authors.affiliation: Laboratory of Tumor and Developmental Biology, GIGA-R, University of Liège, Tour de Pathologie (B23), Sart Tilman, Liège, Belgium.
authors.forename: Marie-Caroline
authors.initials: MC
authors.lastname: Masereel
authors.affiliation: Analytical Chemistry Laboratory, CIRM, Institute of Pharmacy, University of Liège, and Arlenda s.a., Sart Tilman, Liège, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Rozet
authors.affiliation: Veterinary Integrated Research Unit, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Kirschvink
authors.affiliation: Laboratory of Tumor and Developmental Biology, GIGA-R, University of Liège, Tour de Pathologie (B23), Sart Tilman, Liège, Belgium; Department of Obstetrics and Gynecology, University of Liège, Hôpital la Citadelle, Liège, Belgium.
authors.forename: Michelle
authors.initials: M
authors.lastname: Nisolle
authors.affiliation: Laboratory of Tumor and Developmental Biology, GIGA-R, University of Liège, Tour de Pathologie (B23), Sart Tilman, Liège, Belgium.
authors.forename: Carine
authors.initials: C
authors.lastname: Munaut
mesh_terms: D000818:Animals; D003198:Computer Simulation; D005260:Female; D023421:Models, Animal; D008954:Models, Biological; D009010:Monte Carlo Method; D006080:Ovarian Follicle / Q000502:physiology; D010053:Ovary / Q000502:physiology*; D018456:Reproductive Medicine / Q000379:methods*; D018401:Sample Size; D012756:Sheep / Q000502:physiology*