Factors affecting the cryosurvival of mouse two-cell embryos.
A series of 4 experiments was conducted to examine factors affecting the survival of frozen-thawed 2-cell mouse embryos. Rapid addition of 1.5 M-DMSO (20 min equilibration at 25 degrees C) and immediate, rapid removal using 0.5 M-sucrose did not alter the frequency (mean +/- s.e.m.) of blastocyst development in vitro when compared to untreated controls (90.5 +/- 2.7% vs 95.3 +/- 2.8%). There was an interaction between the temperature at which slow cooling was terminated and thawing rate. Termination of slow cooling (-0.3 degrees C/min) at -40 degrees C with subsequent rapid thawing (approximately 1500 degrees C/min) resulted in a lower frequency of blastocyst development than did termination of slow cooling at -80 degrees C with subsequent slow thawing (+8 degrees C/min) (36.8 +/- 5.6% vs 63.9 +/- 5.7%). When slow cooling was terminated between -40 and -60 degrees C, higher survival rates were achieved with rapid thawing. When slow cooling was terminated below -60 degrees C, higher survival rates were obtained with slow thawing rates. In these comparisons absolute survival rates were highest among embryos cooled below -60 degrees C and thawed slowly. However, when slow cooling was terminated at -32 degrees C, with subsequent rapid warming, survival rates were not different from those obtained when embryos were cooled to -80 degrees C and thawed slowly (52.4 +/- 9.5%, 59.5 +/- 8.6%). These results suggest that optimal cryosurvival rates may be obtained from 2-cell mouse embryos by a rapid or slow thawing procedure, as has been found for mouse preimplantation embryos at later stages.(ABSTRACT TRUNCATED AT 250 WORDS)
Critser
J K
JK
Department of Laboratory Medicine, Mayo Clinic, Rochester, Minnesota 55905.
Arneson
B W
BW
Aaker
D V
DV
Huse-Benda
A R
AR
Ball
G D
GD
D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000502:physiology*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005615:Freezing; D051379:Mice; D008815:Mice, Inbred Strains; D011309:Preservation, Biological / Q000379:methods*
D004121:Dimethyl Sulfoxide