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Arsenic and Cigarette Smoke Synergistically Increase DNA Oxidation in the Lung
1 Department of Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85724 Correspondence: Address correspondence to: R. Clark Lantz, College of Medicine, Department of Cell Biology and Anatomy, 1501 North Campbell Avenue, P.O. Box 245044, Tucson, AZ 85724-5044; e-mail:lantz{at}email.arizona.edu Epidemiological evidence has indicated that arsenic and cigarette smoking exposure act synergistically to increase the incidence of lung cancer. Since oxidative damage of DNA has been linked to cancer, our hypothesis is that aerosolized arsenic and cigarette smoke work synergistically to increase oxidative stress and increase DNA oxidation in the lung. To test this hypothesis male Syrian golden hamsters were exposed to room air (control), aerosolized arsenic compounds (3.2 mg/m3 for 30 minutes), cigarette smoke (5 mg/m3 for 30 minutes), or both smoke and arsenic. Exposures were for 5 days/week for 5 or 28-days. Animals were sacrificed one day after the last exposure. In the 28-day group, glutathione levels and DNA oxidation (8-oxo-2'-deoxyguanosine (8-oxo-dG)) were determined. Our results show that in the 28-day arsenic/smoke group there was a significant decrease in both the reduced and total glutathione levels compared with arsenic or smoke alone. This correlated with a 5-fold increase in DNA oxidation as shown by HPLC. Immunohistochemical localization of 8-oxo-dG showed increase staining in nuclei of airway epithelium and subadjacent interstitial cells. These results show that dual exposure of arsenic and cigarette smoke at environmentally relevant levels can act synergistically to cause DNA damage.
Key Words: Arsenic • Cigarette Smoke • Inhalation • DNA Oxidation Abbreviations: DNA, Deoxyribose nucleic acid • 8-oxo-dG, 8-oxo-2'-deoxyguanosine • HPLC, High Pressure Liquid Chromatography • GSH, Glutathione • ROS, Reactive Oxygen Species • TNF-alpha, Tumor Necrosis Factor-alpha • RNS, Reactive Nitrogen Species • BAP, benzo(a)pyrene • DMAV, Dimethylarsenic Acid • As2O3, Arsenic Trioxide • HCl, Hydrochloric Acid • Ca2As5, Calcium Arsenate • As2S3, Arsenic Trisulfide • GSSG, Reduced Glutathione • GaAs, Gallium Arsenide • InAs, Indium Arsenide • BAL, Bronchoalveolar Lavage • MRP1, Multidrug Resistance Protein • BSO, Buthionine Sulfoximine
Toxicologic Pathology, Vol. 34, No. 4,
396-404 (2006) This article has been cited by other articles:
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