High-protein diets contribute to an increase in urea follicular concentrations associated with decreased fertility. Urea has been shown to interfere with the epidermal growth factor (EGF)/EGFR system, which has been shown to have a beneficial effect during in vitro maturation (IVM) of oocytes. Of note, the number of cumulus-oocyte complexes (COCs) in the maturation medium can change the maturation and the developmental competence of COCs. Therefore, it was hypothesized that, the presence of urea and EGF may have a differential effect on the depletion/appearance of AAs and competence of COCs matured individually (I-IVM system) or in groups (G-IVM system). In the G-IVM system, COCs increased consumption (depletion) of AAs compared with other groups in the presence of high-level urea (40 mg/dl) + EGF (10 ng/ml). In the I-IVM system, the non-cleaved COCs depleted more AAs than the cleaved COCs, in particular in the presence of urea. The combination of urea and EGF increased the depletion of AAs in the G-IVM system. However, the EGF abrogated the urea-induced depletion of AAs by the I-IVM COCs. The use of N-acetyl-l-cysteine as an EGFR inhibitor canceled urea-induced depletion of AAs. This shows the inhibiting effect of urea over the EGF/EGFR system. In the presence of urea + EGF, COCs had a lower degree of developmental competence than control in both I- and G-IVM systems. Arginine had the best predictive power to identify highly competent COCs in the G-IVM system, while glutamine was the best predictor of the cleavage in the I-IVM system. In conclusion, this multi-level study shows that COCs matured individually or in groups may have different association with AAs metabolism. These findings provide new insights into the relationships between AA metabolism and the subsequent developmental competence of COCs.

高蛋白饮食有助于增加与生育能力下降相关的尿素卵泡浓度。尿素已被证明会干扰表皮生长因子 (EGF)/EGFR 系统，该系统已被证明在卵母细胞的体外成熟 (IVM) 过程中具有有益作用。值得注意的是，成熟培养基中卵丘-卵母细胞复合体 (COC) 的数量可以改变 COC 的成熟和发育能力。因此，假设尿素和 EGF 的存在可能对单独成熟（I-IVM 系统）或成组成熟（G-IVM 系统）的 AA 的消耗/外观和 COC 的能力产生不同的影响。在 G-IVM 系统中，与其他组相比，在高水平尿素 (40 mg/dl) + EGF (10 ng/ml) 的情况下，COCs 增加了 AA 的消耗（消耗）。在 I-IVM 系统中，未裂解的 COC 比裂解的 COC 消耗更多的 AA，尤其是在尿素存在的情况下。尿素和 EGF 的组合增加了 G-IVM 系统中 AA 的消耗。然而，EGF 消除了尿素诱导的 I-IVM COC 对 AA 的消耗。指某东西的用途N-乙酰-1-半胱氨酸作为EGFR抑制剂取消了尿素诱导的AA消耗。这表明尿素对 EGF/EGFR 系统的抑制作用。在尿素 + EGF 的存在下，COC 在 I- 和 G-IVM 系统中的发育能力都低于对照。精氨酸对识别 G-IVM 系统中的高活性 COC 具有最佳预测能力，而谷氨酰胺是 I-IVM 系统中裂解的最佳预测因子。总之，这项多层次的研究表明，单独或成组成熟的 COC 可能与 AA 代谢具有不同的关联。这些发现为 AA 代谢与 COC 随后的发育能力之间的关系提供了新的见解。