Effect of salbutamol and inhaled sodium cromoglycate on the airway and neutrophil chemotactic activity in "fog"-induced bronchospasm

To investigate whether salbutamol and sodium cromoglycate (SCG) inhibit airway response and the associated mediator release induced by ultrasonic nebulation of distilled water (UNDW, "fog"), we measured the serum neutrophil chemotactic activity (NCA) during bronchial challenge with "fog" with and without premedication with placebo, salbutamol, or SCG in 10 subjects with asthma, in four sets of studies. To assess changes in airway caliber, we measured FEV₁. To assess changes in NCA, we measured the maximal distance reached by neutrophils in a filter when neutrophils were challenged with the subject's serum in a Boyden chamber. Treatment with placebo did not change baseline FEV₁ or serum NCA; however, FEV₁ decreased and serum NCA increased (p <0.05) after inhalation of "fog." Treatment with SCG did not affect either FEV₁ and baseline serum NCA. After inhalation of "fog," no significant bronchoconstriction nor NCA increase was observed in eight of 10 patients with maximal mean percent decrease in FEV₁ of -4.26, SEM 0.99, and maximal mean percent increase in NCA of +8.6, SEM 5.28. In the two patients who developed a bronchoconstriction after challenge with SCG pretreatment, an associated significant increase in NCA was observed but did not affect baseline NCA. After inhalation of "fog," no significant decrease in FEV₁ (maximal mean percent decrease FEV₁, -6.71, SEM 0.17) nor significant increase in serum NCA (maximal mean percent increase NCA, +3.6, SEM 7.1) was observed in nine of 10 patients. After salbutamol, only one patient developed a bronchoconstrictive response to "fog" associated with a significant increase in serum NCA. These results suggest that both SCG and salbutamol may prevent the bronchoconstriction induced by "fog" by inhibiting mediator release.