School of Environmental Science and Engineering, Shandong Key Laboratory of Water Pollution Control and Resource Reuse，, China-America CRC for Environment and Health of Shandong Province, Shandong University, Qingdao, China.
Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou, China.
J Mol Recognit. 2019 Nov;32(11):e2804. doi: 10.1002/jmr.2804. Epub 2019 Aug 2.
Microplastic pollution attracted extensive attention because of its global presence and adverse effects on ecosystem. However, it is insufficient to clear the effects of nanoplastics on organisms at the molecular level. Herein, a nanopolystyrene (50 nm) was used to examine molecular responses of superoxide dismutase (SOD) and desoxyribonucleic acid (DNA) using spectroscopy (UV-vis, circular dichroism spectra, and fluorescence measurements) and single cell gel electrophoresis methods. Results showed that nanopolystyrene induced oxidative stress, involving in the increase of SOD activity and malondialdehide (MDA) content, and DNA damage because of the significant increase of olive tail moment, head optical density, and tail DNA percentage in the groups at exposure concentrations above 5 × 10 mol/L. The second structural and microenvironment of aromatic amino acids of SOD were changed with nanopolystyrene exposure. The fluorescence of SOD was quenched by nanopolystyrene at exposure concentration above 1 × 10 mol/L, and the quenching mode could be ascribed to the static type. The results and the combined methods are favorable to explore the molecular toxicity of other nanoplastics and the interaction mechanism.
微塑料污染因其在全球范围内的存在及其对生态系统的不良影响而引起了广泛关注。然而，要在分子水平上清楚了解纳米塑料对生物体的影响还远远不够。在此，我们使用纳米聚苯乙烯（50nm）通过光谱（紫外可见光谱、圆二色光谱和荧光测量）和单细胞凝胶电泳方法来研究超氧化物歧化酶（SOD）和脱氧核糖核酸（DNA）的分子反应。结果表明，纳米聚苯乙烯会引起氧化应激，包括 SOD 活性和丙二醛（MDA）含量的增加，并且由于暴露浓度高于 5×10-6mol/L 的组中橄榄拖尾矩、头部光密度和尾部 DNA 百分比的显著增加，导致 DNA 损伤。SOD 的芳香族氨基酸的二级结构和微环境随着纳米聚苯乙烯的暴露而发生变化。纳米聚苯乙烯在暴露浓度高于 1×10-6mol/L 时会猝灭 SOD 的荧光，猝灭模式可以归因于静态类型。这些结果和综合方法有利于探索其他纳米塑料的分子毒性及其相互作用机制。
