Fibre Toxicology Division, Indian Institute of Toxicology Research, Lucknow 226001, India; Department of Zoology, University of Lucknow, Lucknow 226007, India.
Environ Toxicol. 2014 Apr;29(4):394-406. doi: 10.1002/tox.21766. Epub 2012 Feb 13.
We have characterized the physicochemical properties of nanotalc particles from two different geographical regions and examined their toxicity mechanisms in human lung epithelial (A549) cells. Indigenous nanotalc (IN) of Indian origin and commercial nanotalc (CN) of American origin were used in this study. Physicochemical properties of nanotalc particles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), Brunauer-Emmet-Teller (BET), and dynamic light scattering (DLS). Results showed that both IN and CN particles significantly induce cytotoxicity and alteration in cell cycle phases. Both IN and CN particles were found to induce oxidative stress indicated by induction of reactive oxygen species (ROS), lipid peroxidation, and depletion of antioxidant levels. DNA fragmentation and caspase-3 enzyme activation due to IN and CN particles exposure were also observed. We further showed that after iron chelation, IN and CN particles produce significantly less cytotoxicity, oxidative stress, and genotoxicity to A549 cells as compared with nonchelated particles. In conclusion, this study demonstrated that redox active iron plays significant role in the toxicity of IN and CN particles, which may be mediated through ROS generation and oxidative stress.
我们对来自两个不同地理区域的纳米滑石颗粒的物理化学性质进行了表征，并研究了它们在人肺上皮（A549）细胞中的毒性机制。本研究使用了来自印度的本土纳米滑石（IN）和来自美国的商业纳米滑石（CN）。通过 X 射线衍射（XRD）、透射电子显微镜（TEM）、能谱（EDS）、BET 和动态光散射（DLS）对纳米滑石颗粒的物理化学性质进行了表征。结果表明，IN 和 CN 颗粒均显著诱导细胞毒性和细胞周期相的改变。研究发现，IN 和 CN 颗粒均诱导氧化应激，表现为活性氧（ROS）的诱导、脂质过氧化和抗氧化水平的消耗。IN 和 CN 颗粒暴露后还观察到 DNA 片段化和 caspase-3 酶的激活。我们进一步表明，与未螯合颗粒相比，铁螯合后，IN 和 CN 颗粒对 A549 细胞的细胞毒性、氧化应激和遗传毒性显著降低。总之，本研究表明，具有氧化还原活性的铁在 IN 和 CN 颗粒的毒性中起重要作用，这可能是通过 ROS 生成和氧化应激介导的。
