Weathered microplastics (MPs) exhibit different physicochemical properties compared to pristine MPs, thus, their effects on the environment and living organisms may also differ. In the present study, we investigated the gut-toxic effects of virgin polypropylene MPs (PP) and UV-weathered PP MPs (UV-PP) on zebrafish. The zebrafish were exposed to the two types of PP MPs at a concentration of 50 mg/L each for 14 days. After exposure, MPs accumulated primarily within the gastrointestinal tract, with UV-PP exhibiting a higher accumulation than PP. The ingestion of PP and UV-PP induced gut damage in zebrafish and increased the gene expression and levels of enzymes related to oxidative stress and inflammation, with no significant differences between the two MPs. Analysis of the microbial community confirmed alterations in the abundance and diversity of zebrafish gut microorganisms in the PP and UV-PP groups, with more pronounced changes in the PP-exposed group. Moreover, the Kyoto Encyclopedia of Genes and Genomes pathway analysis confirmed the association between changes in the gut microorganisms at the phylum and genus levels with cellular responses, such as oxidative stress, inflammation, and tissue damage. This study provides valuable insights regarding the environmental impact of MPs on organisms.

中文翻译：

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暴露于聚丙烯微塑料的斑马鱼肠道毒性和微生物组影响的比较：紫外线风化对微生物组的有趣影响

与原始 MP 相比，风化微塑料 (MP) 表现出不同的物理化学特性，因此，它们对环境和生物体的影响也可能不同。在本研究中，我们研究了原生聚丙烯 MP (PP) 和紫外线风化 PP MP (UV-PP) 对斑马鱼的肠道毒性作用。将斑马鱼暴露于浓度各为 50 mg/L 的两种 PP MP 中 14 天。暴露后，MP 主要在胃肠道内积累，UV-PP 的积累量高于 PP。摄入 PP 和 UV-PP 会引起斑马鱼肠道损伤，并增加与氧化应激和炎症相关的基因表达和酶水平，但两种 MP 之间没有显着差异。微生物群落分析证实，PP 和 UV-PP 组中斑马鱼肠道微生物的丰度和多样性发生了变化，其中 PP 暴露组的变化更为明显。此外，京都基因和基因组百科全书途径分析证实了门和属水平的肠道微生物变化与细胞反应（例如氧化应激、炎症和组织损伤）之间的关联。这项研究提供了有关 MP 对生物体的环境影响的宝贵见解。