Fipronil (FPN) is a widely used phenylpyrazole pesticide that can kill pests by blocking γ-aminobutyric acid (GABA)-gated chloride channels. In addition, there are lack of studies on the effects of FPN on the female mammalian gametes. In this study, porcine oocytes were used to investigate the effects of FPN on the oocyte maturation process. The results showed that the first polar body extrusion rate significantly decreased (100 μM FPN vs. control, 18.64 ± 2.95% vs. 74.90 ± 1.50%, respectively), and oocytes were arrested at the germinal vesicle stage in 100 μM FPN group. Meanwhile, the FPN caused a significant increase in reactive oxygen species (ROS) levels and severe DNA damage inside the oocytes. Furthermore, apoptosis was enhanced along with decreases in mitochondrial membrane potential, BCL-xL, and the release of cytochrome C in FPN-treated group. Additionally, low CDK1 activity and delayed cyclin B1 degradation during germinal vesicle breakdown were found in the FPN-treated group, which resulted from the activation of ATM-P53-P21 pathway. In conclusion, FPN induces apoptosis and cell cycle arrest in porcine oocyte maturation because of increased ROS levels and DNA damage. This suggests that the FPN in the environment may have potential detrimental effects on the female mammalian reproductive system.

中文翻译：

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在体外成熟过程中，Fipronil诱导猪卵母细胞凋亡和细胞周期停滞。

Fipronil（FPN）是一种广泛使用的苯基吡唑农药，可通过阻止γ-氨基丁酸（GABA）门控的氯离子通道杀死害虫。另外，缺乏关于FPN对雌性哺乳动物配子的作用的研究。在这项研究中，猪卵母细胞用于研究FPN对卵母细胞成熟过程的影响。结果表明，第一极体挤出率显着降低（100μMFPN与对照组相比，分别为18.64±2.95％与74.90±1.50％），卵母细胞在100μMFPN组的生小泡期停滞。同时，FPN导致卵母细胞内的活性氧（ROS）水平显着增加和严重的DNA损伤。此外，细胞凋亡随着线粒体膜电位BCL-xL的降低而增强，FPN治疗组细胞色素C的释放。此外，在FPN处理组中发现发芽水泡破坏期间CDK1活性低和细胞周期蛋白B1降解延迟，这是由于ATM-P53-P21途径的激活所致。总之，由于ROS水平和DNA损伤的增加，FPN在猪卵母细胞成熟中诱导凋亡和细胞周期停滞。这表明环境中的FPN可能会对雌性哺乳动物的生殖系统产生潜在的有害影响。