title: Cryopreservation time does not decrease follicular viability in ovarian tissue frozen for fertility preservation.
abstract: OBJECTIVE
  To determine the effect of storage duration on cryopreserved ovarian tissue using fresh and frozen-thawed samples.
  
  
  METHODS
  Seventeen fertile patients underwent an ovarian biopsy during elective laparoscopic tubal ligation. The tissue sample was divided into three parts: one part was processed fresh (FG), and two were slowly frozen, cryopreserved for 30 (G30) or 180 days (G180), thawed and analyzed. Follicular density, follicular viability, and steroidogenic capacity were assessed.
  
  
  RESULTS
  We observed no differences between the groups in follicular density, which was assessed in hematoxylin and eosin-stained tissue sections. A heterogeneous follicular distribution was observed in the parenchyma, with a mean density of 361.3±255.4, 454.9±676.3, and 296.8±269.0 follicles/mm(3) for FG, G30 and G180, respectively (p = 0.46). Follicular viability was greater in FG (93.4%) when compared with the cryopreserved tissues (70.8% for G30 (p<0.001) and 78.4% for G180 (p<0.001)), with no difference in viability between the frozen samples (p>0.05). The steroidogenic capacity of the tissue was not significantly reduced following cryopreservation.
  
  
  CONCLUSIONS
  The slow freezing procedures used for ovarian cryopreservation are capable of preserving follicular viability and maintaining the steroidogenic capacity of the tissue despite a roughly 30% decrease in follicular viability. Furthermore, short-term storage of ovarian tissue does not appear to compromise follicle integrity.
authors.affiliation: Universidade de São Paulo, Department of Obstetrics and Gynecology, Ribeirão Preto/SP, Brazil.
authors.forename: Jacira Ribeiro
authors.initials: JR
authors.lastname: Campos
authors.forename: Julio Cesar
authors.initials: JC
authors.lastname: Rosa-e-Silva
authors.forename: Bruno Ramalho
authors.initials: BR
authors.lastname: Carvalho
authors.forename: Alessandra Aparecida
authors.initials: AA
authors.lastname: Vireque
authors.forename: Marcos Felipe
authors.initials: MF
authors.lastname: Silva-de-Sá
authors.forename: Ana Carolina Japur de Sá
authors.initials: AC
authors.lastname: Rosa-e-Silva
mesh_terms: D000328:Adult; D015925:Cryopreservation / Q000379:methods*; D004801:Eosine Yellowish-(YS); D005260:Female; D059247:Fertility Preservation / Q000379:methods*; D006416:Hematoxylin; D006801:Humans; D006080:Ovarian Follicle / Q000166:cytology* / Q000502:physiology; D011446:Prospective Studies
chemical_list: D004801:Eosine Yellowish-(YS); D006416:Hematoxylin