Activation of Pig Oocytes using Calcium Ionophore: Effect of the Protein Kinase Inhibitor 6-dimethyl aminopurine

The aim of our study was to investigate the parthenogenetic activation of in vitro matured pig oocytes after their combined treatment with calcium ionophore A 23187 and the inhibitor of protein kinases, 6-dimethylaminopurine (6-DMAP) and to study the further embryonic development of oocytes activated using this treatment. The oocytes were exposed to ionophore (10, 25 or 50  μ M ) for 0.5, 1, 3, 5 or 7 min and then cultured with 6-DMAP (0 or 2  μ M ) The highest activation rate (up to 88% of the activated eggs reached the pronuclear stage) was observed after combined treatment of the oocytes with 50  μ M ionophore and 6-DMAP. The highest rate of embryonic development was observed after treatment with 25  μ M ionophore without 6-DMAP, when up to 51% of the eggs developed beyond two-cell stage, 2% of the eggs developed up to the stage of morula and up to 3% of the eggs reached the stage of blastocyst. When 50  μ M ionophore was used, the embryonic development of the activated eggs was arrested before the morula and blastocyst stage. After treatment of the activated eggs with 6-DMAP, we did not observe any development beyond the stage of 16 blastomeres. We can conclude that combined treatment with calcium ionophore A 23187 and 6-DMAP increases the activation rate in pig oocytes matured in vitro , but this combined treatment exerts a detrimental effect on further embryonic development of the activated eggs.