Activation of in vitro matured pig oocytes by combined treatment of ethanol and cycloheximide

Activation of meiosis in oocytes by artificial means is important in studies of oocyte function. In pigs, it seems that treatment with ethanol alone is inadequate for efficient activation of oocytes. Data collected in cattle, suggested that addition of a protein synthesis inhibitor increased the effectivness of ethanol for oocyte activation. We investigated the combined effects of exposure to ethanol and to the protein synthesis inhibitor cycloheximide, on activation of in vitro-matured pig oocytes. Treatment with ethanol alone (concentrations 0, 5, 7 and 10 %) for intervals of up to 3 minutes resulted in very limited activation rates (max, 15 %), A culture of IVM pig oocytes with cycloheximide alone (10 mu g/ml) for 24 hours did not induce oocyte activation either. However, exposure of IVM pig oocytes to 7 and 10 % ethanol followed by culture with cyloheximide substantially increased the activation rate. A maximal activation rate (over 80 %) was observed when oocytes were treated with 10 % ethanol for 1 min and subsequently cultured with cycloheximide.