Changes in the Response of Lung Mast Cells Isolated from Rats and Guinea Pigs Exposed to Nitrogen Dioxide

Abstract

To clarify the relationship between exposure to nitrogen dioxide (NO₂) and mast-cell responses, rats and guinea pigs were exposed to 0, 1.0, 2.0, and 4.0 ppm NO₂ for 12 wk. Although lung wet weights were not changed in both rats and guinea pigs, the number of lung cells from 2.0 and 4.0 ppm NO₂-exposed rats were significantly decreased compared to that of control. No difference was observed in the number of lung mast cells from rats and guinea pigs exposed to NO₂. in lung mast cells from rats, immunoglobulin E (IgE) mediated histamine release was slightly decreased, but A23187-induced histamine release was not changed. On the contrary, in lung mast cells from guinea pigs, IgE-mediated histamine release was increased in a dose-dependent fashion, though no changes in A23187-induced histamine release were observed. These results suggest that different sensitivity for NO₂ exposure exists in lung mast cells from rats and guinea pigs.