Article

Single-Walled Carbon Nanotubes Induces Oxidative Stress in Rat Lung Epithelial Cells

Molecular Neurotoxicology Laboratory/Proteomics Core, Department of Biology, Texas Southern University, Houston, TX 77004, USA.
Journal of Nanoscience and Nanotechnology (Impact Factor: 1.34). 08/2007; 7(7):2466-72. DOI: 10.1166/jnn.2007.431
Source: PubMed

ABSTRACT Single-walled carbon nanotubes (SWCNT) show unique properties find applications in micro devices; electronics to biological systems specially drug delivery and gene therapy. However the manufacture and extensive use of nanotubes raises concern about its safe use and human health. Very few studies have been carried out on toxicity of carbon nanotubes in experimental animals and humans, thus resulted in limiting their use. The extensive toxicological studies using in vitro and in vivo models are necessary and are required to establish safe manufacturing guidelines and also the use of SWCNT. These studies also help the chemists to prepare derivative of SWCNT with less or no toxicity. The present study was undertaken to determine the toxicity exhibited by SWCNT in rat lung epithelial cells as a model system. Lung epithelial cells (LE cells) were cultured with or without SWCNT and reactive oxygen species (ROS) produced were measured by change in fluorescence using dichloro fluorescein (DCF). The results show increased ROS on exposure to SWCNT in a dose and time dependent manner. The decrease in glutathione content suggested the depletion and loss of protective mechanism against ROS in SWCNT treated cells. Use of rotenone, the inhibitor of mitochondrial function have no effect on ROS levels suggested that mitochondria is not involved in SWCNT induced ROS production. Studies carried out on the effect of SWCNT on superoxide dismutase (SOD-1 and SOD-2) levels in LE cells, indicates that these enzyme levels decreased by 24 hours. The increased ROS induced by SWCNT on LE cells decreased by treating the cells with 1 mM of glutathione, N-Acetyl Cysteine, and Vitamin C. These results further prove that SWCNT induces oxidative stress in LE cells and shows loss of antioxidants.

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    • "It has been previously reported that genotoxicity effects can result from the direct interaction of nanoparticles with genetic material or secondary damage resulting from particle-induced reactive oxygen species production (Kisin et al., 2011). According to the recent in vitro studies, SWCNTs and MWCNTs induce ROS production in mammalian cells (Sharma et al., 2007; Shvedova et al., 2003; Ye et al., 2009, 2011). In a previous in vivo 5-day inhalation study by the current authors, a 2.57 mm average tube length induced an increased concentration of intracellular H 2 O 2 with a similar trend of DNA damage (Kim et al., 2012b). "
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