Effects of chronic inhalation exposure to diesel exhaust on the development of lung tumors in di-isopropanol-nitrosamine-treated F344 rats and newborn C57BL and ICR mice

Abstract

Long-term exposure to diesel exhaust from a small diesel engine was carried out in order to elucidate the effects of exhaust on the development of lung tumors in F344 rats and newborn ICR and C57BL mice. The deposition of inhaled particles progressed in accordance with duration of exposure in both sets of the animals. No evidence of lung tumor formation was detected following exposure to diesel exhaust alone in rats. However, the combined treatment with DIPN and diesel exhaust led to an overadditive effect in the development of lung tumors. There was a tendency for the diesel-exposed mice to have higher incidences of lung tumors compared with non-exposed mice. The results obtained in the present study suggest that diesel exhaust may act as a factor relating to human respiratory carcinogenesis.