X-Message-Number: 9488
Date: Tue, 14 Apr 1998 21:07:02 -0700 (PDT)
From: Doug Skrecky <>
Subject: membrane effects of ethylene glycol

Biology of Reproduction 55: 161-168 1996
"Changes in Membrane Integrity, Cytoskeletal Structure, and Developmental
Potential of Murine Oocytes After Vitrification in Ethyelene Glycol"


   A systematic approach was taken to access and optimize a protocol for
intracellular vitrification by introducing high concentrations of the
cryoprotectant agent (CPA) ethylene glycol (EG) into unfertilized murine
oocytes. The effects of EG on membrane integrity, microfilament
organization, and developmental potential were evaluated. During exposure
to 0.5-2 M EG, oocytes showed maximum shrinkage to 55.5% of the isotonic
volume within the first minute and reexpanded to their initial volume
within 15 min. Transferral of oocytes to higher concentrations of EG (4-8 M
EG) for 1-5 min after 15 min of equilibration at 2 M eg was tolerated well.
Microfilament organization appeared normal after this equilibration period.
During prolonged exposure (>5 min) to high concentrations of EG (>4M),
membrane blebs were noticed on the surface of the cells, and microfilament
distribution was disturbed. After treatment with 6 M EG and vitrification
with 6M EG + 0.5 M sucrose, there were no significant differences in
development to the two cell and blastocyst stages between CPA-treated,
vitrified, and control oocytes. These results indicate that EG is an
effective CPA for mouse oocyte vitrification protocols without any observed
compromise in morphology and developmental functions.

Additional quote from text of  report:

   "EG experiments were also carried out in the presence of sucrose, a
well-known membrane stabilizer, to minimize the deleterious effects of high
EG concentrations on membrane integrity. When oocytes equilibrated in 2 M
EG for 15 min were exposed to concentrations of EG between 4 and 8 M with
the addition of 0.5 M sucrose, bleb formation was completely suppressed for
all EG concentrations tested for 30 min."

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