title: Cryopreservation of mouse embryos at morula/compact stage.
abstract: OBJECTIVE
  The objective of this article was to study mouse morula/compact stage embryo postthaw survival rates and postthaw developmental potential.
  
  
  METHODS
  Mouse morula/compact stage embryos were classified into 3 substages. Their morphological behavior during the freezing and thawing process were examined. Postthaw survival rates and blastocyst formation rates were compared between the three substages and the pronucleate and the 2-cell stage embryos. Finally, Postthaw fully compacted and late compact embryos were transferred to foster mothers.
  
  
  RESULTS
  Blastomeres of early compacting embryos separated from each other during the freezing process, whereas in fully compacted and late compact stages, the blastomeres remain compacted. Fully compacted and late compact stage embryos had higher Postthaw survival rates than other stages, though those were not statistically significant (P > 0.05). These two substages had significantly higher blastocyst formation rates than Postthaw pronucleate and early compacting embryos (P < 0.01). A total of 72 Postthaw fully compacted and late compact embryos were transferred and 20 live offspring were delivered.
  
  
  CONCLUSIONS
  After passing early compacting stage, fully compacted and late compact stage mouse embryos have high Postthaw survival rates and significantly higher blastocyst formation rates. Successful cryopreservation of embryos at these two substages has a significant value in embryo selection. The results obtained in this study may provide useful information for human assisted reproductive technology.
authors: Arizona Institute of Reproductive Medicine, 3411 North 5th Avenue, Suite 207, Phoenix, Arizona 85013, USA.
authors: J
authors: J
authors: Tao
authors: R
authors: R
authors: Tamis
authors: K
authors: K
authors: Fink
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology; D048429:Cell Size; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer; D005260:Female; D008297:Male; D051379:Mice; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D009028:Morula / Q000166:cytology* / Q000648:ultrastructure; D015996:Survival Rate