Insufficient evidence exists regarding the visible physiological toxic endpoints of MPs exposures on zebrafish larvae due to their small sizes. Herein, the impacts of micro-polystyrene particles (μ-PS) and 100 nm polystyrene particles (n-PS) on the toxicity of cadmium (Cd) through altering neutrophil expressions were identified and quantified in the transgenic zebrafish (Danio rerio) larvae Tg(lyz:DsRed2), and the effects were size-dependent. When exposed together with μ-PS, the amount of neutrophils in Cd treated zebrafish larvae decreased by 25.56% through reducing Cd content in the larvae. By contrast, although n-PS exposure caused lower Cd content in the larvae, the expression of neutrophils under their combined exposure remained high. The mechanism of immune toxicity was analyzed based on the results of metabonomics. n-PS induced high oxidative stress in the larvae, which promoted taurine metabolism and unsaturated fatty biosynthesis in n-PS + Cd treatment. This observation was accordance with the significant inhibition of the activities of superoxide dismutase and catalase enzymes detected in their combined treatment. Moreover, n-PS promoted the metabolic pathways of catabolic processes, amino acid metabolism, purine metabolism, and steroid hormone biosynthesis in Cd treated zebrafish larvae. Nanoplasctis widely coexist with other pollutants in the environment at relatively low concentrations. We conclude that more bio-markers of immune impact should be explored to identify their toxicological mechanisms and mitigate the effects on the environment.

由于斑马鱼幼虫体型小，因此关于 MPs 暴露对它们的可见生理毒性终点的证据不足。在此，通过改变中性粒细胞表达，鉴定并量化了微聚苯乙烯颗粒（μ-PS）和 100 nm 聚苯乙烯颗粒（n-PS）对镉（Cd）毒性的影响，并在转基因斑马鱼（Danio rerio）幼虫Tg中进行了量化。(lyz:DsRed2)，并且效果是大小相关的。当与 μ-PS 一起暴露时，通过降低幼虫中的 Cd 含量，Cd 处理的斑马鱼幼虫的中性粒细胞数量减少了 25.56%。相比之下，尽管 n-PS 暴露导致幼虫中 Cd 含量降低，但在它们的组合暴露下中性粒细胞的表达仍然很高。根据代谢组学结果分析免疫毒性机制。n-PS 在幼虫中诱导高氧化应激，在 n-PS + Cd 处理中促进牛磺酸代谢和不饱和脂肪生物合成。该观察结果与超氧化物歧化酶和过氧化氢酶的活性在其联合处理中检测到的显着抑制一致。此外，n-PS 促进了分解代谢过程、氨基酸代谢、嘌呤代谢、和类固醇激素生物合成在 Cd 处理的斑马鱼幼虫中。纳米塑料与环境中的其他污染物以相对较低的浓度广泛共存。我们得出的结论是，应该探索更多的免疫影响生物标志物，以确定它们的毒理学机制并减轻对环境的影响。