Effects Of Phosphodiesterase Inhibitor On The In Vitro Matuation Of Bovine And Buffalo Oocytes

Effects of phosphodiesterase (PDE) inhibitor on the in vitro maturation (IVM) of bovine and buffalo oocytes were examined in this study, so as to improve the quality of oocytes matured in vitro.Addition of 0.1 mmol/L milrinone to the maturation medium resulted in a significant decrease in the parthenogenetic (PA) cleavage rate of bovine oocytes matured in vitro for 24 h (30.9% vs 40.0%, P<0.05), but did not affect the in vitro fertilization (IVF) cleavage rate of bovine oocytes (68.1% vs 78.1%, P>0.05). When the IVM duration was prolonged to 28h, no difference was found in either IVF cleavage rate (54.7% vs 61.5%) or IVF cleavage rate (65.5% vs 75.0%) between bovine oocytes matured with and without milrinone. When the IVM duration was prolonged to 32h, the IVF cleavage rate of bovine oocytes matured with milrinone was high than that of oocytes matured without milrinone (54.2% vs 39.7%. P<0.05) but the PA cleavage rate was similar between the two groups (52.9% vs 56.2%). The PA and IVF cleavage rate of buffalo oocytes matured in the medium supplemented with 0.1 mmol/L milrionone were lower or significantly than those of oocytes matured in the medium without milrionone in spite of the IVM duration. When buffalo oocytes were cultured with 0.1 mmol/L milrionone for 24h and then in the maturation medium without milrionone for 22h, their PA cleavage rate (57.7%) and blastocyst yield (41.0%) were significantly higher than those of buffalo oocytes cultured in the maturation medium without milrionone for lOh (15.3% and 19.0%, P<0.05) and similar to those of control group oocytes (57.8% and 44.9%).In conclusions, milrinone has a maturation delay effect on bovine oocytes, but can inhibit the maturation of buffalo oocytes reversible. Buffalo oocytes treated with milrinone can resume meiotic maturation and maintain high developmental competence.