X-Message-Number: 9958 Date: Wed, 1 Jul 1998 04:41:54 -0700 (PDT) From: Doug Skrecky <> Subject: more on ethylene glycol 2 Citations: <1> Authors Bautista JA. Takahashi Y. Kanagawa H. Institution Department of Veterinary, Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. jobau:vetmed.hokudai.ac.jp Title In vitro viability of mouse zygotes vitrified in ethylene glycol. Source Japanese Journal of Veterinary Research. 45(4):193-8, 1998 Feb. Abstract A study was made to determine if mouse zygotes can be effectively vitrified in 7 M ethylene glycol in modified Dulbecco's phosphate buffered saline (PB1) and to find out if the development of vitrified-warmed zygotes in vitro can be improved by renewing the culture medium. The results showed that without medium change, vitrification reduced the development of zygotes to the expanded blastocyst stage (p < 0.01). With medium change, the development rate of vitrified-warmed zygotes exposed in 7 M ethylene glycol for 1 or 2 min was similar to that of unvitrified zygotes. However, prolonged exposure (5 min) markedly reduced the development rates of vitrified-warmed zygotes to the expanded blastocyst stage (p < 0.05). When the zygotes were vitrified in 7 M ethylene glycol and diluted at 18 degrees C to 22 degrees C, a slower efflux of ethylene glycol from the cell might have occurred, leading to a toxic effect of ethylene glycol in culture. The development rates of vitrified embryos cultured with medium change at 24 hr did not significantly differ from the untreated control (89.0% vs 96.5%). In conclusion, this study showed that mouse zygotes can be vitrified in 7 M ethylene glycol in PB1 and that changing the culture medium can improve the in vitro development rates of vitrified-warmed zygotes to the expanded blastocyst stage. <2> Authors Bautista JA. Kanagawa H. Institution Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. jobau:vetmed.hokudai.ac.jp Title Current status of vitrification of embryos and oocytes in domestic animals: ethylene glycol as an emerging cryoprotectant of choice. [Review] [41 refs] Source Japanese Journal of Veterinary Research. 45(4):183-91, 1998 Feb. Abstract The cryopreservation of mammalian embryos has become an integral part of methods to control animal reproduction. Numerous vitrification solutions have been formulated with ethylene glycol in combination with macromolecules, sugars and other cryoprotective agents. These indicate that a study of ethylene glycol as a cryoprotectant of choice in vitrification studies would be promising. To understand the cryobiology of ethylene glycol, several factors have to be studied. These are: cryoprotectant toxicity, osmotic stress and temperature at exposure. Understanding these factors could lead to the formulation of vitrification protocols that would lead to higher viability rates after cooling. First, ethylene glycol must be used as the sole cryoprotectant in a solution without macromolecules and sugars. Second, partial dehydration and permeation prior to cooling to subzero temperatures must be studied to achieve accurate exposure and a one-step dilution method. Third, the toxic effects of ethylene glycol must be overcome without sacrificing its vitrification properties by combining step-wise exposure at appropriate temperatures, low concentration and decreased volume. Fourth, the long-term effects of ethylene glycol on exposed or vitrified embryos must be determined. Lastly, the influence of culture on the viability of vitrified embryos must be studied to improve viability rates after warming. [References: 41] Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=9958