title: Long-Time Cooling before Cryopreservation Decreased Translocation of Phosphatidylserine (Ptd-L-Ser) in Human Ovarian Tissue.
abstract: OBJECTIVE
  To translocation (externalization) of phosphatidylserine lead at least the five negative effects observed during cells cryopreservation: hypoxia, increasing of intracellular Ca2+, osmotic disruption of cellular membranes, generation of reactive oxygen species (ROS) and lipid peroxidation. The aim of this study was to test the intensiveness of the phosphatidylserine translocation immediately after thawing and after 45 d xenografting of human ovarian tissue, which was either frozen just after operative removal from patient or cooled before cryopreservation to 5°C for 24 h and then frozen.
  
  
  METHODS
  Ovarian fragments from twelve patients were divided into small pieces in form of cortex with medulla, and randomly divided into the following four groups. Pieces of Group 1 (n=30) were frozen immediately after operation, thawed and just after thawing their quality was analyzed. Group 2 pieces (n=30) after operation were cooled to 5°C for 24 h, then frozen after 24 h pre-cooling to 5°C, thawed and just after thawing their quality was analyzed. Group 3 pieces (n=30) were frozen immediately after operation without pre-cooling, thawed, transplanted to SCID mice and then, after 45 d of culture their quality was analyzed. Group 4 pieces (n=30) were frozen after 24 h pre-cooling to 5°C, thawed, transplanted to SCID mice and then, after 45 d their quality was analyzed. The effectiveness of the pre-freezing cooling of tissuewas evaluated by the development of follicles (histology) and by intensiveness of translocation of phosphatidylserine (FACS with FITC-Annexin V and Propidium Iodide).
  
  
  RESULTS
  For groups 1, 2, 3 and 4 the mean densities of follicles per 1 mm3 was 19.0, 20.2, 12.9, and 12.2, respectively (P1-2, 3-4 >0.1). For these groups, 99%, 98%, 88% and 90% preantral follicles, respectively were morphologically normal (P1-2, 3-4 >0.1). The FACS analysis showed significantly decreased intensiveness of translocation of phosphatidylserine after pre-cooling of frozen tissue (46.3% and 33.6% in Groups 2 and 4, respectively), in contrast with tissue frozen without pre-cooling (77.1% and 60.2 % in Groups 1 and 3, respectively, P1, 3-2, 4 <0.05).
  
  
  CONCLUSIONS
  Long time (24 h) cooling of ovarian tissue to 5°C before cryopreservation decreased translocation of phosphatidylserine that evidences about increases the viability of the cells in the tissue after thawing.
authors.affiliation: Research Group for Reproductive Medicine and IVF-Laboratory, CAM-Xenotransplantation Group, Department of Obstetrics and Genecology, Cologne University, Cologne, Germany.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Isachenko
authors.affiliation: Institute of Biology and Immunology of Reproduction, Sofia, Bulgaria.
authors.forename: Plamen
authors.initials: P
authors.lastname: Todorov
authors.affiliation: Research Group for Reproductive Medicine and IVF-Laboratory, CAM-Xenotransplantation Group, Department of Obstetrics and Genecology, Cologne University, Cologne, Germany.
authors.forename: Evgenia
authors.initials: E
authors.lastname: Isachenko
authors.affiliation: Research Group for Reproductive Medicine and IVF-Laboratory, CAM-Xenotransplantation Group, Department of Obstetrics and Genecology, Cologne University, Cologne, Germany.
authors.forename: Gohar
authors.initials: G
authors.lastname: Rahimi
authors.affiliation: Institute of Microbiology, Sofia, Bulgaria.
authors.forename: Andrey
authors.initials: A
authors.lastname: Tchorbanov
authors.affiliation: Institute of Microbiology, Sofia, Bulgaria.
authors.forename: Nikolina
authors.initials: N
authors.lastname: Mihaylova
authors.affiliation: Institute of Microbiology, Sofia, Bulgaria.
authors.forename: Iliyan
authors.initials: I
authors.lastname: Manoylov
authors.affiliation: Research Group for Reproductive Medicine and IVF-Laboratory, CAM-Xenotransplantation Group, Department of Obstetrics and Genecology, Cologne University, Cologne, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Mallmann
authors.affiliation: Praxisklinik Schoenhauserstrasse, Cologne, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Merzenich
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D017209:Apoptosis; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D006801:Humans; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D006080:Ovarian Follicle / Q000166:cytology* / Q000637:transplantation* / Q000648:ultrastructure; D010718:Phosphatidylserines / Q000032:analysis*; D055815:Young Adult
chemical_list: D010718:Phosphatidylserines