Development of Mice Embryo after Cryopreservation and Thawing

Lee, Kyung Soon; Moon, Shin Yong; Ahn, Jung Ja

Abstract

Cryopreservation has proved to be a highly successful method for long term storage of viable embryos and it is necessary for human embryo cryopreservation in assisted reproductive technology to reduce the risk of multiple gestation and severe ovarian hyperstimulation syndrome as well as contributing to an overall increase in pregnancy rates. Mouse embryo cryopreservation was carried out in order to establish the most ideal developmental stage of embryo for cryopreservation. F1 hybrid mouse embryo were collected according to its developmetnal stage; 1-cell, 2- cell, 4-cell, morula and blastocyst. 1-cell stage embryo were cryopreserved by slow coolingrapid thawing method using PROH(1,2 propanediol) and 2- cell stage embryo and 4-cell stage embryo were cryopreserved by the same method using PROH or DMSO(dimethyl sulfoxide). And morula and blastocyst stage embryo were cryopreserved by the same cooling method using glycerol. The frozen-thawed embryo showed significantly lower(p < 0.05) hatched rate than fresh embryos. The better hatched rate was obtained when the 2-cell embryos were cyropreserved using PROH as a cryoprotectant(p < 0.05). In the case of the 4-cell stage embryos, the results showed no difference in the post thaw survival rate but a better blastocystic development in the DMSO group(49.6%:38.9%)(p > 0.05). The proportion of frozen embryos developing to hatched blastocysts was significantly decreased in 1-cell stage embryos and blastocysts compared to the 2-cell, 4-cell and morula stage embryo(p < 0.05). According to in vitro development of mouse embryo, the highest hatching rate was obtained from 4-cell stage embryo(43.5%), so the ideal cell stage for embryo cryopreservation is 4-cell stage embryo using DMSO as a cryoprotectant.