SummaryThis study aimed to evaluate the effect of regulating phosphatidylinositol 3-kinase (PI3K) activity on the kinetics of oocyte nuclear maturation and the blastocyst rate. To evaluate oocyte viability, nuclear maturation rate and in vitro embryo production, cumulus–oocyte complexes (COCs) were maintained for 0, 10 min, 6 h or 22 h in TCM 199 medium supplemented with 20 nM wortmannin, an inhibitor of PI3K. After each period, COCs were transferred to the same medium without wortmannin and kept under the same conditions until completion of 22 h of in vitro maturation (IVM). To evaluate the effect of time on progression of nuclear maturation, COCs cultivated with 20 nM wortmannin was maintained for 22, 28 or 34 h of IVM. To determine the effect of wortmannin on the activity of maturation-promoting factor (MPF), COCs were kept under IVM conditions in the presence of the inhibitor for 0, 1, 3, 6, or 8 h. Exposure of COCs to wortmannin decreased (P < 0.05) the percentage of oocytes that reached metaphase II (MII) up to 22 h, MPF activity and reduced PI3K activity by 30%. However, after 28 and 34 h, 70% of oocytes reached the MII stage in the presence of inhibitor Moreover, COCs matured in the presence of wortmannin showed an increase (P < 0.05) in the blastocyst rate. These findings suggested that the regulation of the PI3K activity during IVM of bovine COCs interfered with the meiotic progression due to control of MPF activity, positively affecting the blastocyst rate.

中文翻译：

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体外卵母细胞成熟过程中磷脂酰肌醇 3-激酶活性的调节可增加牛囊胚的产生


摘要本研究旨在评估调节磷脂酰肌醇 3 激酶 (PI3K) 活性对卵母细胞核成熟动力学和囊胚率的影响。评估卵母细胞活力、核成熟率和体外胚胎产生时，卵丘-卵母细胞复合物 (COC) 在补充有 20 nM 渥曼青霉素（一种 PI3K 抑制剂）的 TCM 199 培养基中维持 0、10 分钟、6 小时或 22 小时。每个周期后，将 COC 转移至不含渥曼青霉素的相同培养基中，并保持在相同条件下，直至 22 小时完成。体外成熟（IVM）。为了评估时间对核成熟进程的影响，用 20 nM 渥曼青霉素培养的 COC 在 IVM 中维持 22、28 或 34 小时。为了确定渥曼青霉素对成熟促进因子 (MPF) 活性的影响，将 COC 在存在抑制剂的 IVM 条件下保存 0、1、3、6 或 8 小时。 COC 与渥曼青霉素的接触减少（磷< 0.05) 22 小时内达到中期 II (MII) 的卵母细胞百分比、MPF 活性和 PI3K 活性降低 30%。然而，28 和 34 小时后，在存在抑制剂的情况下，70% 的卵母细胞达到了 MII 阶段。此外，在存在渥曼青霉素的情况下成熟的 COC 显示出增加（磷< 0.05) 的囊胚率。这些发现表明，在牛 COC 的 IVM 过程中对 PI3K 活性的调节会由于 MPF 活性的控制而干扰减数分裂进程，从而对囊胚率产生积极影响。