Effect of Papaver rhoeas L. extract on in vitro maturation of sheep oocytes

This study was conducted to determine the effect of Papaver rhoeas L. extract on in vitro maturation (IVM) of sheep oocytes. Sheep ovaries collected from a local abattoir were transported to the laboratory within 2 h after slaughter. The cumulus-oocyte complexes (COCs) were aspirated from follicles (2-6 mm in diameter). Good quality COCs were selected and cultured in TCM 199 supplemented with 0 (control), 25, 50, 100 and 200 mu g/ml of P. rhoeas extract. The COCs were incubated at 38.5 degrees C in humidified atmosphere of 5% CO2 in air for 24 h. After the incubation period, expansion of cumulus cells and the nuclear status of the oocytes were assessed by phase contrast microscopy and Hoechst 33258, respectively. There were no significant differences between treatments in the percentage of cumulus expansion (P > 0.05). The percentage of arrested oocytes at germinal vesicle (GV) stage in the control group was significantly (P < 0.05) higher than other treatments. There were significant (P < 0.05) differences between all concentrations of extract and the control group in the percentage of in vitro maturated oocytes to metaphase II (MII) stage. The oocytes treated with 50 mu g/ml extract achieved the highest percentage of MII stage compared to the control (P < 0.05); however, no significant difference observed between 25,50 and 100 mu g/ml extract. In conclusion, the results of this study show that supplementation of appropriate concentrations of P. rhoeas extract (50 mu g/ml) in maturation medium improve the sheep oocyte maturation rate. Moreover, effects of P. rhoeas extract on oocyte maturation were dependent on the extract concentration in the maturation medium. (c) 2013 Elsevier B.V. All rights reserved.