Aims:
Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) is found in the reproductive tract and has been shown to have beneficial effects when added to embryo culture media in many species including humans [1, 2]. GM-CSF is also found in the ovarian follicle [3] suggesting it may have a role in oocyte maturation. We have previously shown that the addition of GM-CSF to in vitro oocyte maturation (IVM) media improves oocyte developmental competence resulting in increases in blastocyst rate and cell numbers, and implantation and birth rates following frozen embryo transfer in mice. The present study was undertaken to determine if GM-CSF can improve bovine IVM.
Methods:
Cumulus oocyte complexes (COCs) were aspirated from abattoir derived ovaries and matured in 0 or 10 ng/ml of recombinant bovine GM-CSF (Kingfisher, Assay Matrix) in VitroMat media (ARTLabs Solutions) at 38.5C in 6% CO2, in air. Following fertilisation in Research Vitro Fertilisation media (Cook Medical) in 6% CO2 in air, presumptive zygotes were cultured in Research Vitro Cleave (Cook Medical) and VitroBlast (ARTLabs Solutions in 6% CO2; 7% O2; N2 balance), and embryo development examined. Day 8 blastocyst cell numbers were also determined by differential staining and fluorescent imaging. Each group contained approximately 40 COCs and the experiment was replicated 10 times. Data was analysed using a paired t-test.
Results:
GM-CSF significantly increased day 8 blastocyst rate (81.1% vs 70.5%), blastocyst inner cell numbers (43.7 vs 38.3 ), total cell numbers (141.6 vs 128.1), and ICM:TE (0.50 vs 0.44) ratio compared with the control group .
Conclusion:
In conclusion our results suggest that adding GM-CSF to bovine IVM media, improves bovine embryo development.