Comparison between the temperatures of intracellular ice formation in fresh mouse oocytes and embryos and those previously subjected to a vitrification procedure.
When cells that have been subjected to supposedly innocuous freezing or vitrification procedures are used as the source material for subsequent experiments, it is important that they possess or exhibit the same relevant properties as fresh cells. In this study, we compared the temperatures of intracellular ice formation (IIF) in previously vitrified mouse oocytes/embryos with those in fresh intact ones. In the case of MII oocytes, 2-cell embryos, 4-6-cell embryos, and morulae, there are no significant differences (p>0.05); namely, -33.3 degrees C (fresh) vs. -35.4 degrees C (vitrified) with MII oocytes, -40.6 degrees C (fresh) vs. -38.7 degrees C (vitrified) with 2-cell embryos, -38.0 degrees C (fresh) vs. -39.4 degrees C (vitrified) with 4-6-cell embryos, -24.5 degrees C (fresh) vs. -24.2 degrees C (vitrified) with morulae. But, in 8-cell embryos, there is a significant difference (p<0.05) between fresh (-37.9 degrees C) and vitrified (-32.9 degrees C). If we include this significant difference, the overall IIF temperature of fresh cells is 0.74 degrees C lower than that of previously vitrified cells. If we exclude it, the IIF temperature for fresh cells is 0.32 degrees C higher than that for previously vitrified cells. Our conclusion then is that there is no difference between the IIF temperatures of fresh and previously vitrified cells.
Seki
Shinsuke
S
Fundamental and Applied Cryobiology Group, Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-0840, USA.
Mazur
Peter
P
D000818:Animals; D003080:Cold Temperature; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents; D004622:Embryo, Mammalian / Q000737:chemistry*; D005260:Female; D005615:Freezing; D007053:Ice; D007424:Intracellular Fluid / Q000737:chemistry*; D051379:Mice; D009865:Oocytes / Q000737:chemistry*; D044367:Phase Transition
D003451:Cryoprotective Agents; D007053:Ice