Abstract
Sulfur dioxide (SO~2~) is a ubiquitous air pollutant produced by the burning of fossil fuels. In this study, singleโcell gel electrophoresis (the Comet assay) was used to evaluate the DNA damage produced by inhalation exposure of mice to SO~2~. Male and female mice were housed in exposure chambers and treated with 14.00 ยฑ 1.25, 28.00 ยฑ 1.98, 56.00 ยฑ 3.11, and 112.00 ยฑ 3.69 mg/m^3^ SO~2~ for 6 hr/day for 7 days, while control groups were exposed to filtered air. Comet assays were performed on blood lymphocytes and cells from the brain, lung, liver, spleen, kidney, intestine, and testicles of the animals. SO~2~ caused significant, doseโdependent increases in DNA damage, as measured by Olive tail moment, in all the cell types analyzed from both sexes of mice. The results indicate that inhalation exposure to SO~2~ damages the DNA of multiple organs in addition to the lung, and suggests that this damage could result in mutation, cancer, and other diseases related to DNA damage. Further work will be required to understand the ultimate toxicological significance of this damage. These data also suggest that detecting DNA damage in blood lymphocytes, using the Comet assay, may serve as a useful tool for evaluating the impact of pulmonary SO~2~ exposure in human biomonitoring studies. Environ. Mol. Mutagen., 2005. ยฉ 2005 WileyโLiss, Inc.