The enhanced adsorption of pollutants on biofilm-developed microplastics has been proved in many studies, but the ecotoxicological effects of biofilm-developed microplastics on organisms are still unclear. In this study, adult zebrafish were exposed to original microplastics, biofilm-developed microplastics, original microplastics absorbed with oxytetracycline (OTC), and biofilm-developed microplastics absorbed with OTC for 30 days. The intestinal histological damage, intestinal biomarker response, gut microbiome and antibiotic resistance genes (ARGs) profile of zebrafish were measured to explore the roles of biofilm in the effects of microplastics. The results showed that biofilm-developed microplastics significantly increased the number of goblet cells in intestinal epithelium compared with the control group. The biofilm-developed microplastics also induced the oxidative response in the zebrafish intestines, and biofilm changed the response mode in the combined treatment with OTC. Additionally, the biofilm-developed microplastics caused intestinal microbiome dysbiosis, and induced the abundance of some pathogenic genera increasing by several times compared with the control group and the original microplastics treatments, regardless of OTC adsorption. Furthermore, the abundance of ARGs in biofilm-developed microplastics increased significantly compared with the control and the original microplastic treatments. This study emphasized the significant influence and unique role of biofilm in microplastic studies.

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生物膜增强微塑料和土霉素对斑马鱼肠道的相互作用

许多研究已证明生物膜微塑料对污染物的增强吸附作用，但生物膜微塑料对生物体的生态毒理学影响仍不清楚。在这项研究中，成年斑马鱼分别暴露于原始微塑料、生物膜形成的微塑料、土霉素（OTC）吸收的原始微塑料和OTC吸收的生物膜形成的微塑料30天。测量斑马鱼的肠道组织学损伤、肠道生物标志物反应、肠道微生物组和抗生素抗性基因（ARG）谱，以探讨生物膜在微塑料影响中的作用。结果表明，与对照组相比，生物膜形成的微塑料显着增加了肠上皮中杯状细胞的数量。生物膜形成的微塑料还诱导斑马鱼肠道内的氧化反应，生物膜改变了与OTC联合治疗中的反应模式。此外，无论OTC吸附如何，生物膜形成的微塑料都会导致肠道微生物群失调，并导致一些致病菌属的丰度比对照组和原始微塑料处理增加数倍。此外，与对照和原始微塑料处理相比，生物膜形成的微塑料中 ARG 的丰度显着增加。本研究强调了生物膜在微塑料研究中的重大影响和独特作用。