X-Message-Number: 12578
Date: Sat, 16 Oct 1999 08:46:15 -0700 (PDT)
From: Doug Skrecky <>
Subject: vitrification with polyethylene glycol and ethylene glycol

Authors
  Ohboshi S.  Fujihara N.  Yoshida T.  Tomogane H.
Institution
  Department of Animal Science, Nippon Veterinary and Animal Science
  University, Tokyo, Japan. 
Title
  Usefulness of polyethylene glycol for
  cryopreservation by vitrification of in vitro-derived bovine
  blastocysts.
Source
  Animal Reproduction Science.  48(1):27-36, 1997 Jul.
Abstract
  A series of five experiments measured the high survival of bovine blastocysts
  produced in vitro after cryopreservation by vitrification.
  The vitrification solution (designated VS) contained 40% (v/v)
  ethylene glycol, 6% (w/v)
  polyethylene glycol and 0.5 M sucrose in
  phosphate-buffered saline. Embryos developed in vitro at Days 7 and 8 (Day 0
  = insemination day) were exposed in one step to VS for 1 min or two steps
  with 10% ethylene glycol for 5 min and then
  VS for 1 min. In both cases, the embryos were finally cryopreserved in liquid
  nitrogen. After the embryos were warmed rapidly and the VS solution diluted,
  the survival rates were assessed by monitoring hatching rate in vitro. They
  were 13.0% for the one-step and 72.7% for the two-step procedures (P <
  0.001). When embryos were exposed to individual solutions containing 6% (w/v)
  of each of 4 macromolecules (polyethylene
  glycol, BSA, polyvinylpyrrolidone or Ficoll) in the two-step
  protocol and then cryopreserved, the survival rates were 79.3, 34.8, 41.4 and
  57.1%, respectively. After embryos had been exposed to the VS in two steps
  and then cryopreserved, there were no significant differences in survival
  rates when the solutions were diluted with or without sucrose. These results
  indicated that a vitrification solution containing
  polyethylene glycol can be used for
  cryopreservation of bovine blastocysts produced in vitro,
  and that a two-step addition of VS improved the in vitro survival of
  post-warming embryos. It was also shown to be possible to dilute post-warming
  embryos directly without the use of sucrose solution.

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