title: Cryopreservation of nuclear material as a potential method of fertility preservation.
abstract: OBJECTIVE
  To establish a cryopreservation method for female nuclear materials with the aim of creating viable embryos or offspring by nuclear transfer.
  
  
  METHODS
  A randomized controlled study.
  
  
  METHODS
  Clinical and academic research facility.B6D2F1 mice.
  
  
  METHODS
  Female pronuclei (FPNs) and second polar bodies (2PBs) isolated from superovulated mouse zygotes were cryopreserved, thawed, and transferred into donor zygotes.
  
  
  METHODS
  Survival rates after freeze-thaw and blastocyst formation rates were evaluated.
  
  
  RESULTS
  Female pronuclei and 2PBs preserved with three tested methods resulted in survival rates ranging from 11.5% to 85% for FPNs vs. 46.9% to 95.0% for 2PBs and blastocyst formation rates ranging from 0% to 35.5% for FPNs vs. 9.1% to 47.4% for 2PBs. Live birth offspring also resulted from both FPNs and 2PBs preserved with vitrification.
  
  
  CONCLUSIONS
  We have established a new system to effectively revive frozen nuclei into viable embryos by a combination of nuclei preservation, zygote reconstruction, and coculturing of reconstructed zygotes with mouse embryonic fibroblast cells. Our data suggest that the preserved female genomic DNA material can be potentially used for future nuclear transfer to preserve female fertility.
authors.affiliation: Institute for Reproductive Medicine, The Center for Reproductive Medicine and Infertility, Weill Medical College of Cornell University, New York, New York10021, USA.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: He
authors.forename: Hung Ching
authors.initials: HC
authors.lastname: Liu
authors.forename: Zev
authors.initials: Z
authors.lastname: Rosenwaks
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology*; D002467:Cell Nucleus / Q000648:ultrastructure*; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer; D005260:Female; D005298:Fertility / Q000502:physiology*; D005307:Fertilization in Vitro / Q000379:methods; D005347:Fibroblasts / Q000166:cytology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008815:Mice, Inbred Strains; D011247:Pregnancy; D011256:Pregnancy Outcome; D015044:Zona Pellucida / Q000648:ultrastructure; D015053:Zygote / Q000166:cytology