Study Of Vitrification Of Human Early Cleaved Embryos In Protocol Of Ethylene Glycol And Dimethyl Sulphoxide

Objective To compare the outcome of vitrification solution containing different concentration of ethylene glycol (EG) and dimethyl sulphoxide (DMSO) for cryopreserving human cleaved embryos by vitrification with straws.To select an effective kind of vitrification solution containing EG and DMSO for the clinic.Method EG and DMSO with two different concentration (20%,25%) respectively consisted of four kinds of vitrification solution.Human waste embryos of cleavage stage after in vitro fertilization were vitrified by the four kinds of vitrification solution with straws,compared with the slow controlled-rate freezing.All samples were cryopreserved for about one month,After thawing,the survival rates and subsequent development rates up to blastocyst stage were evaluated through the embryo morphology.Then the survival embryos were stained by Rhodamine 123 to visualize the mitochondrial membrane potential under the laser scanning confocal microscope (LSCM).Result The four kinds of vitrification solution containing different concentration of EG and DMSO were effective in cryopreserving embryos by vitrification.The embryo survival rate of E20D20,E20D25,E25D20,E25D25 group was 51.0%,72.7%,62.0% and 46.3 % in turn,higher than the one of slow controlled-rate freezing group.The survival rate in the 20% EG and 25% DMSO group was significantly higher than that in the slow freezing group (P<0.05),the difference between the other groups and slow freezing group was not significant.The blastulation rate of each group was 11.8%,18.2%,18.0% and 9.3% in turn,but there was no significant different between each vitrification group and slow freezing group.The mitochondrial membrane potential in the 20% EG and 25% DMSO group which was the highest was similar to that of the fresh group and significant higher than the other groups except the E25D25 group. Compared to the fresh group,the mitochondrial membrane potential in the slow controlled-rate freezing group was significant lower(P=0.001).Conclusion 1.The vitrification solution containing EG and DMSO can be effective in cryopreserving human cleaved embryos by vitrification.2.The vitrification solution containing 20%EG and 25%DMSO can not only obtain higher embryo survival rate but also conserve the embryo vitality.It is more effective to cryopreserve human early cleaved embryos.3.The experiment outcome manifests the effect of vitrification is better than the slow controlled-rate freezing.