X-Message-Number: 9542
Date: Thu, 23 Apr 1998 21:01:11 -0700 (PDT)
From: Doug Skrecky <>
Subject: glycerol and sucrose

Authors
  Isachenko VV.  Isachenko EF.  Ostashko FI.  Grishchenko VI.
Institution
  Department of Animal Reproduction, Institute for Animal Science, Kharkov,
  Ukraine.
Title
  Ultrarapid freezing of rat embryos with rapid dilution of permeable
  cryoprotectants.
Source
  Cryobiology.  34(2):157-64, 1997 Mar.
Abstract
  The purpose of this study was to determine the feasibility of ultrarapid
  freezing of rat morulae with rapid postthaw dilution of permeable
  cryoprotectants in isotonic culture medium. Four experiments were carried
  out. Experiment 1 examined the possibility of using vitrification with
  postthaw dilution of permeable cryoprotectants in an isotonic solution.
  Embryos were exposed first to 10% glycerol + 20% propylene glycol and then to
  the final vitrification solution which contained 25% glycerol + 25% propylene
  glycol. Embryo survival was very low when the subsequent dilution was in a
  solution that did not contain sucrose. In Experiment 2. three mixtures were
  tested: 15% glycerol + 15% ethylene glycol + 0.7 M sucrose, 15% glycerol +
  15% propylene glycol + 0.7 M sucrose, and 30% glycerol + 0.7 M sucrose. The
  third mixture, which contained only glycerol and sucrose, produced the best
  results with 88% embryo survival. In Experiment 3, the embryos were frozen in
  30% glycerol plus 0.7 M sucrose and in addition were exposed to 1 M sucrose
  for 7 min following thawing. The survival rate was 85% with the sucrose
  dilution step, 91% when dilution was in isotonic medium, and 95% in controls
  not exposed to the cryoprotective mixture. Experiment 4 examined the effect
  of the time and temperature of exposure of the embryos to 30% glycerol + 0.7
  M sucrose. The highest rates of embryo development followed exposure at 4
  degrees C for 2-3 min (95-84%) or at 24 degrees C for 0.5-3.0 min (90-88%).
  These results indicate that it is possible to develop a method for the
  ultrarapid freezing of mammalian embryos that does not require dilution of
  permeable cryoprotectants in a hypertonic sucrose solution.

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