Toxicological sciences : an official journal of the Society of Toxicology
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Comparative Study
Cigarette smoke exposure produces more evidence of emphysema in B6C3F1 mice than in F344 rats.
Cigarette smoke (CS) causes pulmonary emphysema in humans, but results of previous studies on CS-exposed laboratory animals have been equivocal and have not clearly demonstrated progression of the disease. In this study, morphometry and histopathology were used to assess emphysema in the lungs of B6C3F1 mice and Fischer-344 rats. The animals were exposed, whole-body, to CS at a concentration of 250 mg total particulate matter/m3 for 6 h/day, 5 days/week, for either 7 or 13 months. ⋯ Inflammatory lesions within the lungs of mice contained significantly more neutrophils than those lesions in rats. These results suggest that B6C3F1 mice are more susceptible than F344-rats to the induction of emphysema by this CS exposure regimen and that in mice the emphysema may be progressive. Furthermore, the type of inflammatory response may be a determining factor for species differences in susceptibility to emphysema induction by CS exposure.