Abstract
The relationship between airway hyperresponsiveness and polymorphonuclear leukocytes in the airway has been investigated in recent years. In the present study, airway responsiveness to methacholine and counts of total cells, polymorphonuclear leukocytes and mononuclear cells in bronchoalveolar lavage fluids (BALF) were examined at successive intervals up to six hours after saline or endotoxin inhalation in guinea pigs. The following results were obtained. 1) In the controls, no changes were observed in either cell counts in BALF or airway responsiveness during the six hours after saline inhalation. 2) In the endotoxin (ET)-inhalation groups, counts of total cells and polymorphonuclear leukocytes were unchanged at 30 minutes and 1 hour, but increased remarkably at 3 hours and 6 hours after endotoxin inhalation, although the mononuclear cell count showed no change with time. 3) In the ET-inhalation groups, airway responsiveness was slightly increased at 30 minutes, and then significantly increased at 1 hour and 3 hours after ET-inhalation. At 6 hours, airway responsiveness returned to the base line level and no difference from pre-ET values was found. After ET-inhalation, polymorphonuclear leukocytes infiltrate into the airway. However, the increments of airway responsiveness and of polymorphonuclear leukocytes in BALF showed a time lag indicating no direct correlation between them.
