College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
Chem Res Toxicol. 2012 Jul 16;25(7):1512-21. doi: 10.1021/tx3002093. Epub 2012 Jun 27.
The toxicity of CuO nanoparticles (NPs) to human lung epithelial (A549) cells was investigated in this study. CuO NPs (10-100 mg/L) had significant toxicity to A549 cells, whereas CuO bulk particles (BPs) showed much lower toxicity (24 h IC(50), 58 and 15 mg/L for CuO BPs and NPs, respectively). Transmission electron microscopic analysis demonstrated CuO NP entry into A549 cells and organelles, including lysosomes, mitochondria, and nucleus. Endocytosis was the primary pathway of CuO NPs uptake. CuO NPs (15 mg/L) induced mitochondrial depolarization, possibly mediated by reactive oxygen species (ROS) generation. Intracellular CuO NPs first generate ROS, which subsequently induces the expression of p38 and p53 and ultimately causes DNA damage (Comet assay). We confirm for the first time that the primary cytotoxic response is oxidative stress rather than DNA damage. A fraction of the CuO NPs was exported to the extracellular environment. In this study, centrifugal ultrafiltration tubes were successfully employed to determine the dissolved Cu(2+) from CuO NPs in the cell medium. Dissolved Cu(2+) ions contributed less than half of the total toxicity caused by CuO NPs, including ROS generation and DNA damage. This study provided useful data for understanding transport and toxicity of metal oxide NPs in human cells.
本研究考察了氧化铜纳米颗粒（CuO NPs）对人肺上皮（A549）细胞的毒性。CuO NPs（10-100mg/L）对 A549 细胞具有显著毒性，而氧化铜体（CuO BPs）的毒性则低得多（24 h IC50 分别为 58 和 15mg/L）。透射电子显微镜分析表明 CuO NPs 进入了 A549 细胞和细胞器，包括溶酶体、线粒体和细胞核。内吞作用是 CuO NPs 摄取的主要途径。CuO NPs（15mg/L）诱导线粒体去极化，可能是由活性氧（ROS）的产生介导的。细胞内的 CuO NPs 首先产生 ROS，进而诱导 p38 和 p53 的表达，最终导致 DNA 损伤（彗星试验）。我们首次证实，主要的细胞毒性反应是氧化应激，而不是 DNA 损伤。一部分的 CuO NPs 被运到细胞外环境。在这项研究中，离心超滤管成功地用于测定细胞培养基中 CuO NPs 释放的溶解态 Cu（2+）。溶解态的 Cu（2+）离子对 CuO NPs 引起的总毒性的贡献不到一半，包括 ROS 的产生和 DNA 损伤。本研究为理解金属氧化物 NPs 在人类细胞中的传输和毒性提供了有用的数据。
