Purpose  

To investigate the effect of laser-assisted hatching and necrotic blastomere removal on the development of vitrified–warmed mouse embryos.

Methods  

The vitrified–warmed four-cell stage mouse embryos were divided into five groups; vitrified intact with no laser-assisted hatching, vitrified intact with laser-assisted hatching, vitrified damaged with neither laser assisted hatching nor necrotic blastomere removal, vitrified damaged with laser-assisted hatching, and vitrified damaged with necrotic blastomere removal. Thereafter blastocyst formation, blastomere and apoptotic cell number within all groups were statistically compared.

Results  

The rate of blastocyst formation showed a significant improvement in the group vitrified intact with laser-assisted hatching. However, neither laser-assisted hatching nor necrotic blastomere removal can improve a delayed vitrified–warmed damaged embryos in term of blastocyst formation and total cell number. Nevertheless, apoptotic cell number was significantly reduced after application of both techniques.

Conclusions  

Laser-assisted hatching can improve the development of vitrified–warmed intact four-cell stage mouse embryos, whereas necrotic blastomere removal has no significant effect on the development of vitrified–warmed four-cell stage damaged embryos.