The present research investigated the effects of exposure to sublethal concentrations of cadmium selenide/zinc sulfide (CdSe_core/ZnS_shell)-containing quantum dots (QDs; 0 – 100 µg/L QDs) on the neurophysiological performance of developing zebrafish (Danio rerio). The results suggested that exposure to CdSe QDs for 5 days increased the whole-body content of Cd without affecting the general physiological conditions of larvae. Interestingly, CdSe QD exposure reduced swimming distance but increased swimming velocity of larvae, suggesting that the exposure may lead to burst/episodic swimming. The findings also suggested that CdSe QD exposure reduced the wall-hugging behavior of larvae during a sudden light-to-dark transition test, and that the exposure significantly decreased the locomotor activity of fish during the dark period. On the other hand, control larvae displayed a dark avoidance behavior, whereas CdSe QD-exposed larvae exhibited an increase in the time spent in the dark zone, providing further support that CdSe QDs inhibited anxiety-related responses in larvae. Additional analysis with droplet digital PCR revealed that CdSe QD exposure altered the mRNA levels of genes that are associated with dopamine signaling and oxidative stress response. Collectively, our findings suggested that CdSe QD exposure may induce neurobehavioural toxicity and alters the mRNA abundance of dopamine- and oxidative stress-related genes in developing animals.

本研究调查了暴露于亚致死浓度的硒化镉/硫化锌（CdSe_核/ZnS_壳）的量子点（QD；0 – 100 µg/L QD）对发育中的斑马鱼 ( Danio rerio ) 神经生理学性能的影响。）。结果表明，暴露于 CdSe 量子点 5 天会增加全身 Cd 含量，而不会影响幼虫的一般生理状况。有趣的是，CdSe QD 暴露减少了游泳距离，但增加了幼虫的游泳速度，这表明暴露可能导致爆发/间歇性游泳。研究结果还表明，CdSe QD 暴露降低了幼虫在突然的明暗过渡测试中的抱壁行为，并且暴露显着降低了鱼在黑暗期间的运动活动。另一方面，对照幼虫表现出黑暗回避行为，而暴露于 CdSe QD 的幼虫表现出在暗区花费的时间增加，进一步支持 CdSe QD 抑制幼虫中与焦虑相关的反应。液滴数字 PCR 的其他分析表明，CdSe QD 暴露改变了与多巴胺信号传导和氧化应激反应相关的基因的 mRNA 水平。总的来说，我们的研究结果表明，CdSe QD 暴露可能会诱导神经行为毒性，并改变发育中动物中多巴胺和氧化应激相关基因的 mRNA 丰度。