A. Papi et al., Bronchopulmonary inflammation and airway smooth muscle hyperresponsivenessinduced by nitrogen dioxide in guinea pigs, EUR J PHARM, 374(2), 1999, pp. 241-247
We investigated whether acute exposure to nitrogen dioxide (NO2) causes maj
or inflammatory responses (inflammatory cell recruitment, oedema and smooth
muscle hyperresponsiveness) in guinea pig airways. Anaesthetised guinea pi
gs were exposed to 18 ppm NO2 or air for 4 h through a tracheal cannula. Br
onchoalveolar lavage was performed and airway microvascular permeability an
d in vitro bronchial smooth muscle responsiveness were measured. Exposure t
o NO2 induced a significant increase in eosinophils and neutrophils in bron
choalveolar lavage fluid, microvascular leakage in the trachea and main bro
nchi (but not in peripheral airways), and a significant in vitro hyperrespo
nsiveness to acetylcholine, electrical field stimulation, and neurokinin A,
but not to histamine. Thus, this study shows that in vivo exposure to high
concentrations of NO2 induces major inflammatory responses in guinea pig a
irways that mimic acute bronchitis induced by exposure to irritant gases in
man. (C) 1999 Elsevier Science B.V. All rights reserved.