Significant differences in the cellular and molecular reactions of rat andhamster lung after quartz exposure

Exposure of rats to high doses of quartz and other insoluble isometric part icles can produce lung tumors. In contrast, after exposure of such particle s in hamsters no tumor outcome has been observed. Recent studies have demon strated that the tumorigenic effect of particles is closely linked to the i nduction of inflammatory processes and the subsequent formation and persist ence of mutagenic oxidative DNA-modifications. Species-specific differences in sensitivity to particles should therefore be reflected in the molecular reaction of the lung cells. We exposed rats and hamsters to two different doses of quartz (0.3 mg, 1.2 mg/100 g body weight) by intratracheal instill ation and characterized the dose-related pattern of pulmonary inflammation (neutrophil recruitment, TNF), toxicity (protein content, surfactant phosph olipids), antioxidant defence (glutathione content), mutagenicity (8-oxogua nine, p53) and proliferation. Our results clearly demonstrate a significant ly higher response of the rat to quartz exposure for all determined molecul ar anti cellular parameters. Therefore the examination of these parameters in humans it would contribute to the evaluation of the relevance of rats or hamsters as models to predict particle-induced human lung cancer risk. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.