Biopsy of mouse embryo fertilized in vitro as a preclinical model for preimplantation genetic diagnosis

In preimplantation genetic diagnosis, it is vital that the biopsy method does not affect embryonic development and yet provides a suitable specimen for genetic diagnosis. This study investigated whether the expulsion method, a modification of the displacement and extrusion methods, could satisfy the above mentioned conditions. Mouse embryos fertilized in vitro were biopsied at the 4, 8 and 16-cell stages, and were subsequently observed for in vitro and in vivo development. The rates of blastocyst formation, implantation, and fetal growth in the 8- and 16-cell biopsy groups were not significantly different from those in the control groups, but all 3 parameters were significantly reduced in the 4-cell group. Fetal and placental development was similar to the control group when embryos were biopsied at all three stages. Single blastomeres obtained by expulsion biopsy were subjected to DNA amplification by dual PCR, and Sry and myogenin sequences were amplified. In conclusion, expulsion biopsy did not affect the development of 8- and 16-cell embryos, and the specimens obtained were adequate for DNA amplification.