Abstract
It has been reported that drug such as steroid hormones or anticancer agents show suppressive effects on lung defenses in which alveolar macrophages (AM) play an important role. In this study, five drugs which are frequently used for the treatment of respiratory diseases were investigated as to whether they affect the AM function.
When the drugs were added in vitro to monolayers of the AM obtained from normal rabbit lungs, epinephrine and tyloxapol increased NBT reduction by AM. On the other hand, orciprenaline, bromhexine and aminophylline suppressed NBT reduction by AM as compared to controls.
Inhalation experiments with these drugs in vivo revealed that in the presence of normal pulmonary washings (PW), AM obtained from bromhexine-inhaled rabbits showed more enhanced NBT reduction than did AM obtained from saline-inhaled rabbits.
The discrepancy between in vitro and in vivo effects of bromhexine on AM function is probably due to the influences of alveolar lining materials, because the AM which were stimulated by the PW from bromhexine-inhaled rabbits produced more superoxide than did the AM stimulated by the PW from saline-inhaling rabbits.
These results suggest that some inhalants affect the AM function directly or indirectly, resulting in the alterations of lung defenses.
