摘要
      越来越多的证据表明，微塑料和土霉素（OTC）会影响生物，但很少有研究调查它们对水生生物的联合影响。在本研究中，成年斑马鱼（Danio rerio）暴露于微米、纳米聚苯乙烯塑料和OTC的单一和二元联合污染中30天，并测量了斑马鱼的肠道组织病理学、肠道微生物群和抗生素耐药性基因（ARGs）。结果表明，肠上皮损伤随着塑料尺寸的减小而增加。纳米塑料、OTC及其联合暴露会导致肠道上皮损伤，与微米塑料共同暴露会减少单一OTC暴露造成的肠道损伤。肠道微生物群落受到微塑料和OTC联合暴露的影响。与空白对照相比，在45–85μm微塑料（MOTC）和40–54 nm纳米塑料（NOTC）的OTC处理中，梭杆菌的相对丰度分别增加了12.7%和21.1%，在MOTC和NOTC处理中，拟杆菌的相对丰富度分别增加了26.2%和18.6%。MOTC和NOTC对斑马鱼肠道微生物组生物多样性的影响不同；与空白对照相比，MOTC增加了11.3%的生物多样性，而NOTC降低了8.8%。此外，与对照组相比，40–54 nm纳米塑料、MOTC和NOTC处理中ARGs的丰度分别增加了96.9%、96.6%和68.8%。此外，无论是否与OTC联合使用，在微塑料和纳米塑料处理组之间观察到ARGs特性的显著差异。这些结果对于进一步了解微塑料或纳米塑料和抗生素对水生生物的综合生态毒理学影响至关重要。
Abstract
Accumulated evidence has demonstrated that microplastics and oxytetracycline (OTC) affect organisms, but few studies have investigated their combined effects on aquatic organisms. In this study, adult zebrafish (Danio rerio) were exposed to single and binary-combined contamination of micro-, nano-sized polystyrene plastics and OTC for 30 days, and the intestinal histopathology, gut microbiota and antibiotic resistance genes (ARGs) of zebrafish were measured. The results showed that the intestinal epithelial damage increase with the decrease of plastic sizes. Nano-sized plastics, OTC and their combined exposure caused intestinal epithelial damage, and co-exposure with micro-sized plastics reduced the intestinal damage caused by single OTC exposure. The gut microbial communities were affected by the combined exposure to microplastics and OTC. Compared with the blank control, the relative abundance of Fusobacteria increased 12.7 % and 21.1 % in OTC combined with 45–85 μm micro-plastics (MOTC) and 40–54 nm nano-plastics (NOTC), respectively, and that of Bacteroidetes increased 26.2 % and 18.6 % in the MOTC and NOTC treatments, respectively. The effects of MOTC and NOTC on the biodiversity of the zebrafish gut microbiome were different; MOTC increased the biodiversity by 11.3 % compared with the blank control, whereas NOTC decreased the biodiversity by 8.8 % compared with the blank control. Furthermore, the abundance of ARGs in 40–54 nm nano-plastics, MOTC and NOTC treatments was increased 96.9 %, 96.6 % and 68.8 % compared with the control group, respectively. Additionally, significant differences were observed in ARGs characteristics between the micro- and nano-plastics treated groups whether combined with OTC or not. These results are essential to further understand the combined ecotoxicological effects of micro- or nano-plastics and antibiotics on aquatic organisms.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722040141