effects of re-vitrification of mouse morula and early blastocyst stages on apoptotic gene expression and developmental potential

Objective: re-vitrification of embryos immediately after thawing or after a culture period could be used to preserve the extra embryos after embryo transfer. this study aims to clarify the effect of re-vitrification on bax and bcl-2 gene expressions of compact and early blastocyst stage embryos. materials and methods: this experimental study was performed on mouse embryos. we collected 8-cell stage embryos (n=400) from female mature mice, 60-62 hoursafter injection of human chorionic gonadotropin (hcg). the embryos were divided into 5 groups: fresh (n=80), vitrified at the 8-cell stage (n=80), vitrified at the blastocyst stage (n=80), vitrified at the 8-cell stage, and re-vitrified at the compact (n=80) and early blastocyst stages (n=80). embryos were vitrified by cryolock. we analyzed the developmental rates of the vitrified-warmed embryos with the chi-square test. quantitative polymerase chain reaction (qpcr) data were analyzed with spss version 16 using one-way analysis of variance (anova) followed by tukey’s post hoc test. p<0.05 were considered statistically significant. results: the expanded blastocyst formation rate showed a significant difference in re-vitrified embryos compared with fresh embryos (p<0.05). however, this result was similar between the two re-vitrified groups. our data showed a significant difference in expression of the bax and bcl-2 genes between re-vitrified and fresh embryos (p<0.05). expressions of the bax and bcl-2 genes showed no significant difference between the two re-vitrified groups. conclusion: based on our study, re-vitrification could affect developmental rate and expressions of the bax and bcl2 genes.