Enhanced histamine release from lung mast cells of guinea pigs exposed to sulfuric acid aerosols

To clarify the relationship between air pollution and mast cell response, the effects of sulfuric acid aerosols on histamine release from lung mast cells of guinea pigs were investigated. Guinea pigs were exposed to 0.3, 1.0 and 3.2 mg/m 3 sulfuric acid (H 2 SO 4 ) aerosols or 4 ppm nitrogen dioxide (NO 2 ) for 2 and 4 weeks. After the exposure, lung mast cell suspensions were isolated by collagenase treatment and antigen- or A23187-induced histamine release was measured. Antigen-induced histamine release from mast cells was significantly enhanced by the exposure to 1.0 and 3.2 mg/m 3 H 2 SO 4 for 2 weeks, but exposure to H 2 SO 4 for 4 weeks did not show the enhancement of antigen-induced histamine release. A23187-induced histamine release was significantly enhanced by the exposure to 1.0 mg/m 3 H 2 SO 4 or 4 ppm NO 2 for 2 weeks, but suppression of histamine release from lung mast cells stimulated with A23187 was observed by the exposure to 3.2 mg/m 3 H 2 SO 4 for 4 weeks. The exposure to 0.3 mg/m 3 H 2 SO 4 showed no changes in antigen- and A23187-induced histamine release. The combination of 1.0 mg/m 3 H 2 SO 4 with 4 ppm NO 2 for 2 weeks resulted in no changes in antigen- and A23187-induced histamine release. These results suggested that functional properties of lung mast cells may be altered by a low concentration of H 2 SO 4 aerosol exposure.