A Vitrification Method by Means of a Straw to Prevent Infections in Mouse Pronuclear Embryos

Abstract

Mouse p ronuc lear em bryos we re cryopreserved by a simple and safe vitrification method. In the process, Vitrification Media VT101, Thawing Media VT 102 (KITAZATO. Co. Japan) and the embryos were loaded into a straw; then they were cryopreserved. Different loading methods were examined to determine the safety levels of crystallization for the embryo’s survival after thawing. The best condition attained, after thawing, was a 75% embryo survived rate of which 66% developed to the two-cell stage, 71% developed to the morula stage and 27% developed to the blastosyst stage. This development of embryos after vitrification was not significantly different to that of a control group without freezing and thawing. The vitrification method was considered to protect embryos against various infections via liquid nitrogen during cryopreservation. It is expected that the method can be applied to human embryos.