title: Comparison of two freezing protocols in an open freezing system for cryopreservation of rat ovarian tissue.
abstract: OBJECTIVE
  To compare two freezing protocols in an automatic open-vessel freezing system for cryopreservation of rat ovarian tissue.
  
  
  METHODS
  Ovarian tissue was transplanted heterotopically into the neck muscle, either without cryopreservation (group 1, n = 6) or with cryopreservation after equilibration with 1.5 mol/L dimethyl sulfoxide and propanediol (protocol A, group 2, n = 6) or 1.5 mol/L ethyl glycol (protocol B, group 3, n = 6). The ovarian tissue was examined with LIVE/DEAD fluorescent viability staining and histologically after isotransplantation.
  
  
  RESULTS
  The healthy follicular loss (intact oocyte and >50% granulosa cells alive) due to cryopreservation was 15.5% with protocol A and 12.2% with protocol B. Histological examination showed follicles in all developmental phases in all groups: group 1, 35.5 +/- 5.7/mm(2) (mean +/- SD); group 2, 16.0 +/- 5.0/mm(2); group 3, 17.3 +/- 5.7/mm(2). The differences between groups 1 and 2 and between groups 1 and 3 were significant (P < 0.001). The difference between groups 2 and 3 was not significant (P = 0.33).
  
  
  CONCLUSIONS
  These results demonstrate that the use of an open freezing system with both freezing protocols allows cryopreservation of rat ovarian tissue with equally good survival rates.
authors.affiliation: Department of Obstetrics and Gynecology, Erlangen University Hospital, Erlangen, Germany.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Maltaris
authors.forename: Arno
authors.initials: A
authors.lastname: Dimmler
authors.forename: Andreas
authors.initials: A
authors.lastname: Müller
authors.forename: Inge
authors.initials: I
authors.lastname: Hoffmann
authors.forename: Matthias W
authors.initials: MW
authors.lastname: Beckmann
authors.forename: Ralf
authors.initials: R
authors.lastname: Dittrich
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D016377:Organ Transplantation; D006080:Ovarian Follicle; D051381:Rats; D011917:Rats, Inbred Lew; D014021:Tissue Preservation / Q000379:methods*