X-Message-Number: 30831
Date: Wed, 25 Jun 2008 16:06:45 -0700 (PDT)
From: 
Subject: 20% EG + 20% DMSO tops in one test

[This result can not be generalized to organ systems, due to the
requirement for prolonged incubation due to slow permeation of
whole organs. Prolonged incubation is known to greatly increase the
toxicity of most cryoprotectants typically used in vitrification
solutions. Which solution is least toxic can thus depend on the incubation
time. Currently this prolonged incubation time is the major limiting
factor preventing excellent results with small cell samples, from being
generalized to large samples.]

Reprod Fertil Dev. 2008;20(4):490-6.
Effect of type of cryoprotectant on morphology and developmental competence
of in vitro-matured buffalo (Bubalus bubalis) oocytes subjected to slow
freezing or vitrification.
    Gautam SK, Verma V, Palta P, Chauhan MS, Manik RS. Animal Biotechnology
Centre, National Dairy Research Institute, Karnal 132 001, India.
    The present study examined the effects of different cryoprotectants on
morphology and developmental competence of in vitro-matured buffalo oocytes
after slow freezing or vitrification. After slow freezing in dimethyl
sulfoxide (DMSO), ethylene glycol (EG) or 1,2-propanediol (PROH), at 1.0 or
1.5 m each, the proportion of morphologically normal oocytes recovered was
significantly higher (P < 0.05) with 1.5 than 1.0 m for all cryoprotectants
and was highest (P < 0.05) for 1.5 m DMSO. Following vitrification, the
percentage of morphologically normal oocytes recovered was lower (P < 0.01)
for 40% EG than for 40% DMSO, 20% EG + 20% DMSO or 20% EG + 20% PROH. The
most common damage, irrespective of the cryopreservation method, was loss of
cumulus mass. The cleavage rate and the proportion of vitrified-warmed
oocytes that developed to morulae/blastocysts were significantly higher (P <
0.01) for 20% EG + 20% DMSO than for the other groups. A higher proportion
of oocytes developed to morulae (11.5% v. 4.3%) or blastocysts (5.4% v.
0.6%) after vitrification in 20% EG + 20% DMSO than after slow freezing in
1.5 m DMSO. In conclusion, vitrification was more effective than slow
freezing for the cryopreservation of in vitro-matured buffalo oocytes.
PMID: 18462611

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