Addition of GM-CSF during in vitro oocyte maturation improves embryo development and implantation and birth rate in mice.

The present study determined whether adding granulocyte macrophage colony stimulating factor (GM-CSF) during in vitro oocyte maturation (IVM) could improve oocyte developmental competence by examining embryo development and implantation and birth rates following embryo transfer in mice. In an initial dose response experiment, we demonstrated that the addition of 2 and 10 ng/mL of GM-CSF during IVM increased cumulus expansion (P<0.05) but did not affect fertilisation rate compared with the control group. The addition of 10 ng/mL increased blastocyst rate (17.0%; P<0.05) and tended to increase the number of good quality blastocysts present at 96 h of culture (+19.4%; P=0.06) and increased blastocyst inner cell mass (+25.2%; P<0.001), trophectoderm (+29.9%; P<0.01), and total cell numbers (+28.6%; P<0.05). GM-CSF also reduced the incidence of DNA damage in blastocysts in the 10 ng/mL group (-16.2%) compared with the control group. These improvements translated into increases in implantation rate (+21.0%; P<0.05) and birth rate (+17.0%; P<0.05) following the transfer of vitrified blastocysts.GM-CSF treatment did not alter any fetal and placental parameters. Together these results suggest that the addition of GM-CSF during IVM may improve livestock in vitro embryo production and human IVM.