Effect of Endotoxin Inhalation on Airway Responsiveness in Guinea Pigs

Abstract

It has been suggested that airway hyperresponsiveness correlates well with the existence of airway inflammation. In the present study, the relationship between the airway responsiveness to inhaled methacholine and the number of white blood cells in bronchoalveolar lavage fluid was investigated before and after inhalation of endotoxin. Ten cases of guinea pigs with bacterial α-amylase (BA) sensitization and 9 cases without sensitization were studied. Pulmonary resistance and dynamic compliance were employed to record the dose-response curves and provocation concentration was determined.
In group I (4 sensitized and 4 unsensitized), dose-response curves were recorded before and three hours after saline inhalation, and in group II (6 sensitized and 5 unsensitized) dose-response curves were obtained before and three hours after endotoxin inhalation. Bronchoalveolar lavage was performed at the end of the experiment and numbers of white blood cells were counted.
In group I, PC did not change before and after saline inhalation and white blood cell counts in BALF were normal. On the other hand, PC was significantly reduced following endotoxin inhalation and white blood cell counts in BALF were increased after endotoxin especially in sensitized cases.
These results may indicate that airway hyperresponsiveness is closely related to the migration of white blood cells to the airway wall.