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Cellular repair mechanisms triggered by exposure to silver nanoparticles and ionic silver in embryonic zebrafish cells
Environmental Science: Nano ( IF 5.8 ) Pub Date : 2021-07-24 , DOI: 10.1039/d1en00422k
Ana C. Quevedo 1, 2, 3, 4 , Iseult Lynch 1, 2, 3, 4 , Eugenia Valsami-Jones 1, 2, 3, 4
Affiliation  

The potential environmental risks of silver nanoparticles (AgNPs) require advanced toxicological studies that elucidate the intrinsic and extrinsic cellular responses in organisms, triggered by nanoparticle (NP) exposure. As part of our ongoing efforts to confirm the utility of continuously cultured embryonic zebrafish cells (ZF4) as an in vitro aquatic model for nanotoxicology, we evaluated the molecular mechanisms of cytotoxicity and the cellular repair mechanisms triggered after exposure to three AgNP sizes (10 nm, 30 nm and 100 nm) and ionic Ag (as AgNO3) under serum conditions. The results demonstrated the crucial role of the adsorbed protein corona in reducing AgNP cytotoxicity and the time dependent AgNP internalisation. At 2 hours, the NPs were likely to be attached to the cell membranes as part of the first NP-cell encounter, whereas after 24 hours AgNPs were found in lysosomes and in close proximity to the nucleus. The cytotoxicity of PVP-coated AgNPs was size-related, as smaller (10 nm) AgNPs and ionic silver displayed major induction of all evaluated responses compared to the 30 nm and 100 nm AgNPs. All treatments demonstrated overgeneration of reactive oxygen species (ROS) and disruption of the intracellular Ca2+ balance. Cells were able to activate defence mechanisms in response to the induced damage, such as cell cycle arrest which prevented cells reaching the S phase, thereby providing time to repair DNA damage. The smaller AgNPs and the ionic control triggered massive cell cycle arrest, high percentages of DNA breaks and cell death, while exposure to the 100 nm AgNPs led to activation of G1 and G2 phases suggesting that ZF4 cells can overcome the damage. In addition, we evaluated the sequence of molecular events that lead to the toxic mode of action of the AgNPs in cells, supporting the establishment of adverse outcome pathways (AOP) and the 3Rs framework for the reduction of animal experimentation.

中文翻译:

在胚胎斑马鱼细胞中暴露于银纳米粒子和离子银触发的细胞修复机制

银纳米粒子 (AgNP) 的潜在环境风险需要高级毒理学研究,以阐明由纳米粒子 (NP) 暴露引发的生物体内内在和外在细胞反应。作为我们不断努力确认连续培养的胚胎斑马鱼细胞 (ZF4) 作为纳米毒理学体外水生模型的效用的一部分,我们评估了细胞毒性的分子机制和暴露于三种 AgNP 大小(10 nm)后触发的细胞修复机制, 30 nm 和 100 nm) 和离子 Ag(如 AgNO 3) 在血清条件下。结果表明吸附的蛋白质电晕在降低 AgNP 细胞毒性和时间依赖性 AgNP 内化方面的关键作用。在 2 小时时,作为第一次 NP 细胞接触的一部分,NPs 可能附着在细胞膜上,而 24 小时后,在溶酶体中发现 AgNPs 并靠近细胞核。PVP 包覆的 AgNPs 的细胞毒性与尺寸相关,因为与 30 nm 和 100 nm AgNPs 相比,较小 (10 nm) 的 AgNPs 和离子银显示出对所有评估响应的主要诱导。所有处理均显示活性氧 (ROS) 的过度生成和细胞内 Ca 2+ 的破坏平衡。细胞能够激活防御机制以响应诱导的损伤,例如阻止细胞进入 S 期的细胞周期停滞,从而为修复 DNA 损伤提供时间。较小的 AgNPs 和离子控制引发大量细胞周期停滞、高百分比的 DNA 断裂和细胞死亡,而暴露于 100 nm AgNPs 导致 G1 和 G2 期的激活,表明 ZF4 细胞可以克服损伤。此外,我们评估了导致 AgNPs 在细胞中的毒性作用模式的分子事件序列,支持建立不良结果通路 (AOP) 和减少动物实验的 3Rs 框架。
更新日期:2021-07-24
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