Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life Earth and Environment, University of Namur, 61 Rue de Bruxelles, B-5000, Namur, Belgium.
Department of Pharmacy, Namur Nanosafety Center (NNC), Namur Research Institute for Life Sciences (NARILIS), University of Namur, Namur, Belgium.
Environ Sci Pollut Res Int. 2024 Sep;31(45):56523-56535. doi: 10.1007/s11356-024-34955-7. Epub 2024 Sep 13.
Understanding the environmental impact of nanoparticle (NP) mixtures is essential to accurately assess the risk they represent for aquatic ecosystems. However, although the toxicity of individual NPs has been extensively studied, information regarding the toxicity of combined NPs is still comparatively rather scarce. Hence, this research aimed to investigate the individual and combined toxicity mechanisms of two widely consumed nanoparticles, zinc oxide (ZnO NPs) and titanium dioxide (TiO NPs), using an in vitro model, the RTgill-W1 rainbow trout gill epithelial cell line. Sublethal concentrations of ZnO NPs (0.1 µg mL) and TiO (30 µg mL) and a lethal concentration of ZnO NPs causing 10% mortality (EC10, 3 µg mL) were selected based on cytotoxicity assays. Cells were then exposed to the NPs at the selected concentrations alone and to their combination. Cytotoxicity assays, oxidative stress markers, and targeted gene expression analyses were employed to assess the NP cellular toxicity mechanisms and their effects on the gill cells. The cytotoxicity of the mixture was identical to the one of ZnO NPs alone. Enzymatic and gene expression (nrf2, gpx, sod) analyses suggest that none of the tested conditions induced a strong redox imbalance. Metal detoxification mechanisms (mtb) and zinc transportation (znt1) were affected only in cells exposed to ZnO NPs, while tight junction proteins (zo1 and cldn1), and apoptosis protein p53 were overexpressed only in cells exposed to the mixture. Osmoregulation (Na + /K + ATPase gene expression) was not affected by the tested conditions. The overall results suggest that the toxic effects of ZnO and TiO NPs in the mixture were significantly enhanced and could result in the disruption of the gill epithelium integrity. This study provides new insights into the combined effects of commonly used nanoparticles, emphasizing the importance of further investigating how their toxicity may be influenced in mixtures.
了解纳米颗粒 (NP) 混合物的环境影响对于准确评估它们对水生生态系统构成的风险至关重要。然而，尽管已经对单个 NPs 的毒性进行了广泛研究，但有关组合 NPs 毒性的信息仍然相对较少。因此，本研究旨在使用体外模型 RTgill-W1 虹鳟鱼鳃上皮细胞系，研究两种广泛使用的纳米颗粒，氧化锌 (ZnO NPs) 和二氧化钛 (TiO NPs) 的单独和联合毒性机制。基于细胞毒性测定，选择亚致死浓度的 ZnO NPs (0.1 μg mL) 和 TiO (30 μg mL) 以及导致 10%死亡率的 ZnO NPs 致死浓度 (EC10，3 μg mL)。然后，将细胞单独暴露于所选浓度的 NPs 及其组合中。细胞毒性测定、氧化应激标志物和靶向基因表达分析用于评估 NP 细胞毒性机制及其对鳃细胞的影响。混合物的细胞毒性与单独的 ZnO NPs 相同。酶和基因表达 (nrf2、gpx、sod) 分析表明，没有一种测试条件会引起强烈的氧化还原失衡。仅在暴露于 ZnO NPs 的细胞中，金属解毒机制 (mtb) 和锌转运 (znt1) 受到影响，而仅在暴露于混合物的细胞中，紧密连接蛋白 (zo1 和 cldn1) 和凋亡蛋白 p53 过度表达。渗透压调节 (Na + /K + -ATPase 基因表达) 不受测试条件的影响。总体结果表明，ZnO 和 TiO NPs 在混合物中的毒性作用显著增强，可能导致鳃上皮完整性受损。本研究提供了对常用纳米颗粒联合效应的新见解，强调了进一步研究其毒性如何在混合物中受到影响的重要性。
