Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, Hefei, 230036, China; Reproductive and Genetic Branch, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China.
Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, Hefei, 230036, China.
Theriogenology. 2022 Feb;179:60-68. doi: 10.1016/j.theriogenology.2021.11.018. Epub 2021 Nov 21.
Paraquat (PQ) is a heterocyclic pesticide that not only damages the testicular development and reduces the quality of semen, but also disturbs the secretion of hormones in the reproductive system. However, the effects of PQ on oocyte maturation and its toxic mechanism have not been yet fully clarified. Here we showed that PQ exposure could have toxic effects on porcine oocyte maturation. PQ exposure with 100 μM inhibited cumulus cell expansion and significantly reduced the rate of first polar body extrusion during oocyte maturation. PQ-exposed oocytes could not develop to the 2-cell and blastocyst stage. PQ exposure with 100 μM significantly increased abnormal spindle rate (65.2% ± 1.0%) and misaligned chromosome rate (63.2% ± 3.4%) compared to the control group (38.3% ± 1.0% and 38.4% ± 1.0%, respectively; P < 0.05). F-actin also exhibited reduced distribution in PQ-exposed oocytes (10.3% ± 1.0%) compared to the control group (14.4% ± 1.0%, P < 0.05). In addition, PQ exposure reduced the active mitochondria levels, but apparently increased the reactive oxygen species (ROS), rH2AX, and LC3 (autophagy marker) levels. qPCR analyses showed that PQ exposure caused the aberrant expression of genes associated with cumulus cell expansion, but did not affect the expression of apoptosis-related genes. Taken together, these results indicate that PQ exposure impaired oocyte nuclear and cytoplasmic maturation probably through oxidative stress.
百草枯（PQ）是一种杂环类农药，不仅会损害睾丸发育，降低精液质量，还会扰乱生殖系统的激素分泌。然而，PQ 对卵母细胞成熟的影响及其毒性机制尚未完全阐明。在这里，我们发现 PQ 暴露对猪卵母细胞成熟具有毒性作用。100μM 的 PQ 暴露会抑制卵丘细胞扩展，并显著降低卵母细胞成熟时第一极体排出的比率。暴露于 PQ 的卵母细胞无法发育至 2 细胞和囊胚阶段。与对照组相比（分别为 38.3%±1.0%和 38.4%±1.0%；P<0.05），暴露于 100μM 的 PQ 会显著增加异常纺锤体比率（65.2%±1.0%）和染色体排列不齐的比率（63.2%±3.4%）。与对照组相比（分别为 14.4%±1.0%和 14.4%±1.0%；P<0.05），暴露于 PQ 的卵母细胞中 F-肌动蛋白的分布也减少。此外，PQ 暴露会降低活性线粒体水平，但明显增加活性氧（ROS）、rH2AX 和 LC3（自噬标记物）水平。qPCR 分析表明，PQ 暴露导致与卵丘细胞扩展相关的基因表达异常，但不影响凋亡相关基因的表达。综上所述，这些结果表明，PQ 暴露可能通过氧化应激损害卵母细胞核和细胞质成熟。
