Abstract
Background: Single-walled carbon nanotubes (SWCNTs) have been reported to induce cytotoxicity in different cell lines. Although the mechanisms underlying cytotoxicity are not fully understood, accumulation of reactive oxygen species (ROS) and oxidative damage is considered to be a likely contributing factor. Methods: Human lung carcinoma cells, A549, and human fetal lung fibroblasts, MRC-5 were used to assess the cytotoxicity of SWCNT in the presence and absence of a redox status regulator, N-acetylcysteine (NAC), via the MTT assay. Results: SWCNT induced a nearly three-fold greater loss of viability in A594 vs. MRC-5 cells at ?250 ?g/ml. SWCNT cytotoxicity at higher concentrations was similar for both cell lines, while NAC alone was non-toxic. The cytotoxicity of SWCNT (250 ?g/ml) in combination with NAC to A549 cells was significantly decreased at the lowest NAC concentration (1.5 ?g/ml), and was similar to NAC treatment alone at that concentration. Higher concentrations of NAC in combination with SWCNT (250 ?g/ml) resulted in increased cytotoxicity in both A549 and MRC-5 cells. Conclusion: A549 malignant lung cells are more susceptible to low concentrations of SWCNT vs. normal lung cells, and low concentrations of N-acetylcysteine appear to be cytoprotective, possibly due to its antioxidant properties.
Highlights
Carbon nanotubes (CNTs) are a distinct molecular form of carbon atoms
A549 malignant lung cells are more susceptible to low concentrations of single-walled carbon nanotubes (SWCNT) vs. normal lung cells, Correspondence to: and low concentrations of N-acetylcysteine appear to be cytoprotective, possibly due to its antioxidant properties
At higher concentrations of SWCNT (>250 μg/ml), cytotoxicity was similar in both cell lines
Summary
Carbon nanotubes (CNTs) are a distinct molecular form of carbon atoms. They were described in 1991 by Sumio Lijima as a tube-shaped, wellordered, flat network of carbon [1]. Several in vitro studies have demonstrated that CNTs exhibit substantial cytotoxicity, possibly via induction of oxidative stress, inhibition of cellular proliferation, and induction of apoptosis/necrosis [12, 13]. Assessment of reactive oxygen species (ROS) production by cells exposed to carbon nanoparticles is an essential part of in vitro cytotoxicity testing. ROS are oxygen-containing molecules with unpaired electrons, and are highly reactive. Oxidative stress occurs when there is an imbalance between oxidants and antioxidants that favors the presence of ROS, due to the excessive Received: 15.02.2013 production of oxidant species and/or depletion of antioxidants
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