纳米银对大型蚤的多世代毒性效应及其致毒机理研究

As one of the most widely used inorganic nano-material, silver nanoparticles (AgNPs) release into aquatic environment through multiple approaches, and then affect the stability and safety of aquatic ecosystem directly. A large number of studies have shown that AgNPs significantly affect the growth, development and reproduetion of aquatic organisms. However, these effects are mainly based on the acute or short-term experiments, long-term and multi-generation toxicity of aquatic organisms are paid little attention. Meanwhile, the mechanism of toxicity is not fully elucidated. To solve the above scientific problems, this project intends to take the model organism of aquatic toxicology studies, Daphnia magna, as the research object. Multi-generation toxicity of Daphnia magna that directly exposed (adding AgNPs directly to the culture medium) and indirectly exposed (feeding Scenedesmus treated with AgNPs) to AgNPs with different particle sizes and different concentrations are investigated through microscopic observation, physiological-biochemical analysis and transcriptome analysis. The biological mechanism is revealed from the perspective of molecular, cellular and morphology. The toxic effect and toxic mechanism of AgNPs to aquatic organisms were elucidated. The results provide evidence for the ecological risk evaluation and prediction of nano-materials, and have important scientific significance and potential application value.

纳米银颗粒（AgNPs）作为使用量最大的无机纳米材料之一，可以通过多种途径进入水体环境，从而影响水生生态系统的稳定和安全。大量研究表明AgNPs显著影响水生生物的生长、发育和繁殖等多个生活史阶段。然而，这些影响主要以急性或短期实验研究结果为基础，缺少对水生生物长期多世代毒性效应的关注，其中的致毒机理也没有完全阐明。针对以上科学问题，本项目拟以水生毒理学研究的模式生物---大型蚤为研究对象，通过显微观察、生理生化分析，转录组分析等环境毒理学研究方法，研究不同粒径、不同浓度AgNPs直接暴露（培养液中直接添加AgNPs）和间接暴露（喂食经AgNPs处理栅藻）对大型蚤的世代毒性效应，解析该过程中的基因表达规律，从分子、细胞和形态学等多角度揭示其生物学机理，阐明AgNPs对水生生物的毒性效应及致毒机理。研究结果为评价和预测纳米材料的生态风险提供依据，具有重要的科学意义和潜在的应用价值。

本项目以水生毒理学研究的模式生物大型蚤为研究对象，通过显微观察、生理生化分析，转录组分析等环境毒理学研究方法，研究了不同浓度、不同粒径（40和110 nm）、不同表面包被的AgNPs（PVP和CIT）暴露对大型蚤的世代毒性效应。研究结果显示，CIT包被的AgNPs毒性效应显著高于PVP包被的AgNPs，且颗粒直径越小所产生的毒性越强，同时，AgNPs对大型蚤的毒性作用呈现世代减小的趋势。转录组测序研究结果表明，AgNPs对大型蚤的毒性机制主要与其关键基因的离子结合功能相关，即从AgNPs释放的银离子可能会与其他金属离子竞争结合功能蛋白，从而导致大型蚤中蛋白质结构和功能发生变化。同时，AgNPs还可以影响大型蚤的几种关键代谢途径，尤其是“RNA聚合酶”和“蛋白质消化吸收”途径。本项目从分子、细胞和形态学等多角度揭示了毒性效应的生物学机制，阐明了AgNPs对水生生物的毒性效应及致毒机理。研究结果可以为评价和预测纳米材料的生态风险提供依据，具有重要的科学意义。项目执行期间共发表SCI论文5篇，培养学生3名，完成了立项之初设定的考核指标。