Abstract
The aim of this study was to develop a simple and rapid method of cryopreservation of rat blastocysts by vitrification. Vitrification solution used here contained glycerol and polyethylene glycol as cryoprotective agents in a HEPES buffered saline (VS3). Two methods of vitrification, one-step and stepwise, were examined to explore a convenient and successful technique for vitrifying rat embryos. No obvious difference was found in post-thaw in vitro survival of vitrified embryos between the two methods of vitrification, suggesting that one-step method may be successful for the vitrification of rat blastocysts. Microscopical observations of the embryos revealed that prolonged exposure of the embryos to the VS3 induced the considerable swelling of embryonic cells, suggesting the intracellular influx of cryoprotective agents. Based on the morphological examinations, no serious damages were observed in the vitrified-thawed embryos after a short period of exposure time (5 min). The present results demonstrate that one-step method of vitrification would be successful for cryo-storage of rat blastocysts.
