The effect of re-vitrification on developmental rate and Bax, Bcl-2& ErbB4 genes expression in mouse embryos

Vitrification as a convenient and effective method for freezing and storing of embryos are known. In some situations, such as unsuitable endometrial, extra embryos could be re-vitrified for using in future. There is inadequate data on the effects of re-vitrification on embryos, so the effects of re-vitrification on the development rate and expression of apoptotic and implantation genes was evaluated
Material and In this study, six-eight week old female (NMRI) mice were used. Mice were super ovulated with 7.5 IU PMSG and 7.5 IU HCG. Females were mated with males from the same strain and inspected for the presence of vaginal plugs on the following morning. Females with the presence of vaginal plugs were considered to be pregnant and were killed 62 h post HCG injection. Eight-cells embryos were flushed from oviduct and divided to three experimental groups including: fresh, vitrified –warmed 8-cells embryos and re-vitrified –warmed blastocyst embryos. Finally, RNA was extracted and expression of Bax, Bcl-2 and ErbB4 genes was evaluated by Real time PCR. Data was analyzed by Chi-square and ANOVA tests.
The results of this study showed that there was significant difference in blastocyst formation rate, degeneration rate and Bax, Bcl-2 & ErbB4 genes expression in re-vitrified embryos comparing with fresh embryos.
According to the result of this study, Vitrification and warming process didn’t effect the developmental rate and Bax and Bcl2 and ErbB4 genes expression in the eight-cell stage embryos, but after re-vitrification in the early blastocyst stage, the development rate and expression of Bax and Bcl2 and ErbB4 genes altered.