title: Preservation of human ovarian follicles within tissue frozen by vitrification in a xeno-free closed system using only ethylene glycol as a permeating cryoprotectant.
abstract: OBJECTIVE
  To study the preservation of follicles within ovarian tissue vitrified using only one or a combination of three permeating cryoprotectants.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  University hospital.
  Ovarian tissue was donated by consenting women undergoing elective cesarean section.
  
  
  METHODS
  Ovarian tissue was vitrified in closed sealed vials using either a combination of dimethyl sulfoxide, 1,2-propanediol, and ethylene glycol (EG), or only EG as permeating cryoprotectants.
  
  
  METHODS
  Ovarian tissue was vitrified with the use of two vitrification methods. Tissue from the same donor was used for comparison of two different solutions. The morphology of the follicles was evaluated after vitrification, warming, and culture by light microscopy and transmission electron microscopy. Apoptosis was assessed by immunohistochemistry for active caspase-3 in fresh and vitrified tissue.
  
  
  RESULTS
  Light and electron microscopic analysis showed equally well preserved morphology of oocytes, granulosa cells, and ovarian stroma when either of the vitrification solutions was used. No apoptosis was observed in primordial and primary follicles.
  
  
  CONCLUSIONS
  Using only EG as a permeating cryoprotectant in a closed tube gives as good ultrastructural preservation of ovarian follicles as a more complicated system using several cryoprotectants.
authors.affiliation: Division of Obstetrics and Gynecology, Department of Clinical, Science, Technology and Intervention, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden. mona.sheikhi@karolinska.se
authors.forename: Mona
authors.initials: M
authors.lastname: Sheikhi
authors.forename: Kjell
authors.initials: K
authors.lastname: Hultenby
authors.forename: Boel
authors.initials: B
authors.lastname: Niklasson
authors.forename: Monalill
authors.initials: M
authors.lastname: Lundqvist
authors.forename: Outi
authors.initials: O
authors.lastname: Hovatta
mesh_terms: D000328:Adult; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000008:administration & dosage*; D019855:Ethylene Glycol / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D006080:Ovarian Follicle / Q000187:drug effects* / Q000502:physiology*; D058989:Vitrification
chemical_list: D003451:Cryoprotective Agents; D019855:Ethylene Glycol