Biochemical and Morphological Alterations in the Lungs and Livers of Mice Following Exposure to Polluted Air in a Traffic Tunnel

The air in the Lin-Shen tunnel in Taipei is heavily polluted due to heavy traffic. To elucidate the biologic effects of air pollution, we studied the biochemical alterations of Polycyclic aromatic hydrocarbons metabolic enzymes and histological changes in the livers and lungs in experimental mice under long-term and short-term exposure to the tunnel air. The concentrations of 16 Polycyclic aromatic hydrocarbons in the air were measured by HPLC, and the mutagenicity of the extract of air particulates was assayed by the Ames test. We found that the benzo(a)pyrene hydroxylase and cytochrome P-450 in the livers and nitroreductase in the lungs of the 30-day exposed animals were significantly increased as compared to the unexposed control (p < 0.005). The nitroreductase in the liver also increased but not significantly. The lungs of long-term (6 mo.) exposed mice showed anthracosis, chronic inflammation, and emphysema (10/10). The livers of the experimental animals did not show significant alteration. A whitish circular nodule appeared on the liver surface of one mouse (1/10). Microscopically, the nodule showed necrosis and hyperchromatic cells around the central vein. It is concluded that the polluted air in the traffic tunnel has evident biohazardous effects on the lungs and livers of mice under the experimental conditions.