The increasing release of engineered nanoparticles (ENPs) in aquatic ecosystems stresses the need for stringent investigations of nanoparticle mixture toxicity towards aquatic organisms. Here, the individual and combined immunotoxicity of two of the most consumed ENPs, the ZnO and the TiO ones, was investigated on rainbow trout juveniles (). Fish were exposed to environmentally realistic concentrations (21 and 210 µg L for the ZnO and 210 µg L for the TiO) for 28 days, and then challenged with the pathogenic bacterium, . Antioxidant and innate immune markers were assessed before and after the bacterial infection. None of the experimental conditions affected the basal activity of the studied innate immune markers and the redox balance. However, following the bacterial infection, the expression of genes coding for pro and anti-inflammatory cytokines ( and ), as well as innate immune compounds () were significantly reduced in fish exposed to the mixture. Conversely, exposure to ZnO NPs alone seemed to stimulate the immune response by enhancing the expression of the and genes for instance. Overall, our results suggest that even though the tested ENPs at their environmental concentration do not strongly affect basal immune functions, their mixture may alter the development of the immune response when the organism is exposed to a pathogen by interfering with the inflammatory response.

中文翻译：

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单一和联合暴露于 ZnO 和 TiO2 纳米颗粒对受到杀鲑气单胞菌无色生成的虹鳟鱼的免疫调节作用


水生生态系统中工程纳米粒子（ENP）释放量的增加强调需要严格研究纳米粒子混合物对水生生物的毒性。在此，研究了两种消耗最多的 ENP（ZnO 和 TiO）对虹鳟鱼幼鱼的单独和联合免疫毒性 ()。将鱼暴露在环境实际浓度（ZnO 为 21 和 210 µg/L，TiO2 为 210 µg/L）中 28 天，然后用致病细菌进行攻击。在细菌感染之前和之后评估抗氧化剂和先天免疫标记物。所有实验条件均不影响所研究的先天免疫标记物的基础活性和氧化还原平衡。然而，在细菌感染后，暴露于混合物的鱼中编码促炎和抗炎细胞因子（和）以及先天免疫化合物（）的基因表达显着降低。相反，单独接触氧化锌纳米颗粒似乎可以通过增强 和 基因的表达来刺激免疫反应。总体而言，我们的结果表明，尽管测试的 ENP 在其环境浓度下不会强烈影响基础免疫功能，但当生物体暴露于病原体时，它们的混合物可能会通过干扰炎症反应来改变免疫反应的发展。