Oxidative DNA Damage in Mouse Heart, Liver, and Lung Tissue Due to Acute Side-Stream Tobacco Smoke Exposure

Environmental tobacco smoke (ETS) is a hotly debated social, political, and scientific issue, pitting smokers’ rights against the health and safety of nonsmokers. Striking an acceptable balance between the two depends largely on the potential health hazard assessment of ETS. Studies from this laboratory have shown that exposure to side-stream cigarette smoke (SSS), the major component of ETS, significantly increases oxidative stress in mouse heart, liver, and lung tissues. This study measures the level of oxidative damage to mouse liver, lung, and heart DNA as a result of this oxidative stress. Adult female Balb/c mice were exposed to a regimen consisting of sequences of a 30-min exposure followed by a 90-min nonexposure. This regimen was performed once for the single exposure and repeated three times for the triple exposure. The heart, lung, and liver were excised from the mice, and DNA was extracted and analyzed for the presence of the oxidative product 8-hydroxy-2′-deoxyguanosine (8-OHdG). In all three tissues, the exposure increased the presence of 8-OHdG above the control levels. In some instances, the increased levels returned to normal by the end of the nonexposure period, while other tissues showed a further increase following nonexposure. These studies demonstrate that limited exposure to SSS produces measurable DNA oxidative damage.