Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
Environ Int. 2021 Jun;151:106452. doi: 10.1016/j.envint.2021.106452. Epub 2021 Feb 24.
Microplastic (MP) is an emerging environmental pollutant and exposure to MPs has been associated with numerous adverse health outcomes in both wild and laboratory animals. The toxicity of MPs depends on concentration, exposure time, chemical composition and size distribution, but the impacts of particle size remain inconclusive yet. In this study, adult marine medaka (Oryzias melastigma) were exposed to different size of polystyrene MPs (PS-MPs) with concentration of 10 mg/L for 60 days and the growth performance, lipid metabolism, immune parameters and gut microbiome were determined. Results indicated that particle size is a dominant factor causing lipid metabolism disorders and hepatic toxicity in PS-MPs-exposed fish. The bodyweight, adipocyte size and hepatic lipid contents were significantly increased in 200 μm PS-MPs-exposed fish, while 2 and 10 μm PS-MPs-exposed fish exhibited liver injury principally manifested asthepresence oflittlefibrosis and inflammation. Given that larger particles could not enter the circulatory system, the impacts of PS-MPs on intestinal microbial biota homeostasis were further investigated. The results not only showed the characterization of gut microbial communities in Oryzias melastigma, but also indicated that microbial diversity and composition were altered in gut of fish exposed to PS-MPs, in particular 200 μm PS-MPs. The differentially abundant bacterial taxa in PS-MPs-exposed fish mainly belonged to the phylum Verrucomicrobia, Firmicutes and Fusobacteria. And furthermore, increased abundance of Verrucomicrobia and Firmicutes/Bacteroidetes ratio and decreased Fusobacteria were correlated with the increased bodyweight. Intestinal microbiome should play a critical role in regulating host lipid metabolism in fish exposed to lager size of PS-MPs.
微塑料（MP）是一种新兴的环境污染物，暴露于微塑料已与野生动物和实验室动物的许多不良健康结果有关。MP 的毒性取决于浓度、暴露时间、化学组成和粒径分布，但粒径的影响尚未确定。在这项研究中，成年海洋稻蝗（Oryzias melastigma）暴露于不同粒径的聚苯乙烯 MPs（PS-MPs）中，浓度为 10mg/L，暴露 60 天，测定生长性能、脂质代谢、免疫参数和肠道微生物组。结果表明，粒径是导致 PS-MPs 暴露鱼类脂质代谢紊乱和肝毒性的主要因素。200μm PS-MPs 暴露组鱼的体重、脂肪细胞大小和肝脂质含量显著增加，而 2μm 和 10μm PS-MPs 暴露组鱼主要表现为肝损伤，伴有少量纤维化和炎症。由于较大的颗粒不能进入循环系统，因此进一步研究了 PS-MPs 对肠道微生物区系稳态的影响。结果不仅显示了 Oryzias melastigma 肠道微生物群落的特征，还表明暴露于 PS-MPs 后鱼肠道微生物群落的多样性和组成发生了改变，特别是 200μm PS-MPs。PS-MPs 暴露组鱼中丰度差异较大的细菌类群主要属于疣微菌门、厚壁菌门和拟杆菌门。此外，疣微菌门和厚壁菌门/拟杆菌门比值的增加以及梭杆菌门的减少与体重的增加相关。肠道微生物组在调节暴露于大粒径 PS-MPs 的鱼类宿主脂质代谢中可能发挥关键作用。
