Methods Mouse embryos were fixed in 4% paraformaldehyde in DEPC-PBS overnight at 4℃.

These experiments were carried out to clarify the kinds, the best concentration of the cryoprotectant which has no or little toxicity to embryos as well as suitable stage of the embryos development by studying on the toxicity experiments of the mouse embryos, so that achieve the aim to improve viability of the frozen embryos.

Experimental study on the cryopreservation and thawing of mouse embryo;

Study of t he effects of cryoprotectant concentrations on mouse embryo development with rapidfreezing method.;