Carbendazim exposure inhibits mouse oocytes meiotic maturation in vitro by destroying spindle assembly

Authors：Cong Ma , Zhuonan Yang , Shouxin Zhang , Xueke Zhang , Siyuan Wang , Huiru Cheng , Yang Liu , Hongzhen Ruan , Zuying Xu , Chunmei Liang , Dan Liang , Zhiming Ding , Yajing Liu , Yunxia Cao

Source：Food Chem Toxicol. 2023 Jul 26;179:113966

DOI:10.1016/j.fct.2023.113966

Abstract：Successful fertilization and early embryonic development heavily depend on the quality of the oocytes. Carbendazim (CBZ), a broad-spectrum fungicide, is widely available in the environment and has adverse effects on organisms. The present study focused on exploring the potential reproductive toxicity of CBZ exposure by investigating its effects on the maturation of mouse oocytes. The results demonstrated that although no disruptions were observed in the G2/M stage transition for meiosis resumption, CBZ did hinder the polar body extrusion (PBE) occurring during oocyte maturation. Cell cycle distribution analysis revealed that CBZ exposure interfered with the meiotic process, causing oocytes to be arrested at the metaphase I (MI) stage. The subsequent investigation highlighted that CBZ exposure impeded the spindle assembly and chromosomal alignment, which was linked to a decline in the level of p-MAPK. Additionally, CBZ exposure adversely affected the kinetochore-microtubule (K-MT) attachment, leading to the persistent activation of the spindle-assembly checkpoint (SAC). The study further noticed a substantial rise in the acetylation of α-tubulin and a reduction in spindle microtubule stability in CBZ-treated oocytes. In addition, the distribution pattern of estrogen receptor alpha (ERα) was altered in oocytes treated with CBZ, with abnormal aggregation on the spindles. CBZ exposure also resulted in altered histone modifications. A notable finding from this research was that the meiotic maturation of some oocytes remained unaffected even after CBZ treatment. However, during the ensuing metaphase II (MII) stage, these oocytes displayed anomalies in their spindle morphology and chromosome arrangement and diminished ability to bind to the sperm. The observations made in this study underscore the potential for CBZ to disrupt the meiotic maturation of oocytes, leading to a decline in the overall quality of oocytes.

摘要：

成功受精和早期胚胎发育在很大程度上取决于卵母细胞的质量。多菌灵（CBZ）是一种广谱杀菌剂，广泛存在于环境中，对生物体有不良影响。本研究通过调查多菌灵对小鼠卵母细胞成熟的影响，重点探讨了接触多菌灵对生殖系统的潜在毒性。结果表明，虽然没有观察到减数分裂恢复的 G2/M 阶段转换受到干扰，但 CBZ 确实阻碍了卵母细胞成熟过程中出现的极体挤压（PBE）。细胞周期分布分析表明，暴露于 CBZ 会干扰减数分裂过程，导致卵母细胞停滞在移行期 I（MI）阶段。随后的调查显示，CBZ 的暴露阻碍了纺锤体的组装和染色体的排列，这与 p-MAPK 水平的下降有关。此外，CBZ 还对动点心轴-微管（K-MT）附着产生了不利影响，导致纺锤体组装检查点（SAC）持续激活。研究进一步注意到，在CBZ处理过的卵母细胞中，α-微管蛋白的乙酰化显著增加，纺锤体微管的稳定性降低。此外，雌激素受体α（ERα）在CBZ处理的卵母细胞中的分布模式也发生了改变，在纺锤体上异常聚集。CBZ还导致组蛋白修饰发生改变。这项研究的一个显著发现是，一些卵母细胞的减数分裂成熟即使在 CBZ 处理后也不受影响。然而，在随后的减数分裂第二阶段（MII），这些卵母细胞的纺锤体形态和染色体排列出现异常，与精子结合的能力减弱。本研究的观察结果表明，CBZ 有可能破坏卵母细胞的减数分裂成熟，导致卵母细胞整体质量下降。