17α-ethynylestradiol (EE2), a synthetic hormone that derives from the natural hormone estradiol, has been reported to alter the sex determination, sexual maturity and secondary sexual characteristics of exposed organisms. However, the adverse effects of EE2 on the oocyte quality have not fully determined. Here, we found that EE2 exposure compromised the fertilization capacity of mouse oocytes, while treatment of melatonin remarkably elevated the fertilization rate. Specifically, we observed that EE2 exposure led to the abnormal distribution and premature exocytosis of ovastacin, leading to the reduced number of sperm binding to the EE2-exposed oocytes. In addition, we found that the abundance of Juno, the sperm receptor on the oocyte membrane, was also diminished, which might be another potential cause leading to the fertilization failure of EE2-exposed oocytes. Finally, we demonstrated that melatonin improved the fertilization ability of EE2-exposed oocytes through eliminating the excessive ROS and inhibiting apoptosis.

中文翻译：

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褪黑素改善了暴露于17α-乙炔基雌二醇的卵母细胞的受精能力。

17α-乙炔基雌二醇（EE2）是一种源自天然激素雌二醇的合成激素，据报道可改变暴露生物的性别决定，性成熟和继发性特征。但是，EE2对卵母细胞质量的不利影响尚未完全确定。在这里，我们发现EE2暴露会损害小鼠卵母细胞的受精能力，而褪黑激素的处理则显着提高了受精率。具体来说，我们观察到EE2暴露导致卵磷脂的异常分布和卵泡过早脱落，从而导致精子与EE2暴露的卵母细胞结合的数量减少。此外，我们发现卵母细胞膜上的精子受体Juno的丰度也降低了，这可能是导致暴露于EE2的卵母细胞受精失败的另一个潜在原因。最后，我们证明褪黑激素通过消除过量的ROS和抑制细胞凋亡，提高了EE2暴露的卵母细胞的受精能力。