褪黑素减轻PNMC诱导的小鼠卵母细胞纺锤体组装和线粒体功能的破坏

Melatonin mitigates PNMC-induced disruption of spindle assembly and mitochondrial function in mouse Oocytes           

褪黑素减轻PNMC诱导的小鼠卵母细胞纺锤体组装和线粒体功能的破坏

Authors: Ma C, Xu Y, Zhang X, Shi X, Zhang Y, Luo M, Wu C, Ding Z, Xiang H, Cao Y.

Source：Ecotoxicol Environ Saf. 2024 Sep 1;282:116703. doi: 10.1016/j.ecoenv.2024.116703.

Abstract

3-methyl-4-nitrophenol (PNMC), a degradation product of organophosphorus insecticides and a byproduct of fuel combustion, exerting endocrine-disrupting effects. However, its impact on the meiotic process of oocytes remains unclear. In the present study, we investigated the effects of PNMC on meiotic maturation of mouse oocytes in vitro and related mechanisms. Morphologically, PNMC-exposure affected germinal vesicle breakdown (GVBD) and polar body extrusion (PBE) in mouse oocytes. Proteomic analysis suggested that PNMC-exposure altered oocyte protein expression that are associated with cytoskeleton, mitochondrial function and oxidative stress. Further studies demonstrated that PNMC-exposure disrupted spindle assembly and chromosome alignment, caused sustained activation of spindle assembly checkpoint (SAC), and arrested meiosis in oocytes. Specifically, PNMC-exposure interfered with the function of microtubule organizing centers (MTOCs) by significantly reducing phosphorylated mitogen activated protein kinase (p-MAPK) expression and disrupting the localization of Pericentrin and p-Aurora A, leading to spindle assembly failure. Besides, PNMC-exposure also increased α-tubulin acetylation, decreased microtubule stability. Moreover, PNMC-exposure impaired mitochondrial function, evidenced by abnormal mitochondrial distribution, decreased mitochondrial membrane potential and ATP levels, release of Cytochrome C into the cytoplasm, and elevated ROS levels. As a result, exposure to PNMC caused DNA damage and early apoptosis in oocytes. Fortunately, melatonin was able to promote oocyte maturation by removing the excessive ROS and enhancing mitochondrial function. These results highlight the adverse effects of PNMC on meiotic maturation, and underscore the protective role of melatonin against PNMC-induced damage.

Keywords: Melatonin; Mitochondria; Oocyte meiosis; PNMC.

摘要

3-甲基-4-硝基苯酚（PNMC）是有机磷杀虫剂的降解产物，也是燃料燃烧的副产品，具有内分泌干扰作用。然而，其对卵母细胞减数分裂过程的影响尚不清楚。本研究探讨了PNMC对小鼠卵母细胞体外成熟的影响及其相关机制。在形态学上，PNMC暴露影响小鼠卵母细胞的萌发囊泡破裂（GVBD）和极体排出（PBE）。蛋白质组学分析表明，PNMC暴露改变了与细胞骨架，线粒体功能和氧化应激相关的卵母细胞蛋白质表达。进一步的研究表明，PNMC暴露破坏了纺锤体组装和染色体排列，导致纺锤体组装检查点（SAC）持续激活，并阻止了卵母细胞的减数分裂。具体来说，PNMC暴露通过显着降低磷酸化有丝分裂原激活蛋白激酶（p-MAPK）表达并破坏Pericentrin和p-Aurora A的定位，从而干扰微管组织中心（MTOCs）的功能，导致纺锤体组装失败。此外，PNMC暴露还增加了微管蛋白的乙酰化，降低了微管的稳定性。此外，PNMC暴露损害线粒体功能，表现为线粒体分布异常、线粒体膜电位和ATP水平降低、细胞色素C释放到细胞质中以及ROS水平升高。因此，暴露于PNMC引起卵母细胞DNA损伤和早期凋亡。幸运的是，褪黑素能够通过清除过量的ROS和增强线粒体功能来促进卵母细胞成熟。这些结果突出了PNMC对减数分裂成熟的不利影响，并强调了褪黑素对PNMC诱导的损伤的保护作用。

关键词：褪黑激素;线粒体;卵母细胞减数分裂; PNMC