TY - JOUR
T1 - Effect of subchronic in vivo exposure to nitrogen dioxide on lung tissue inflammation, airway microvascular leakage, and in vitro bronchial muscle responsiveness in rats
AU - Chitano, Pasquale
AU - Rado, Vanda
AU - Di Stefano, Antonino
AU - Papi, Alberto
AU - Boniotti, Anna
AU - Zancuoghi, Gianna
AU - Boschetto, Piera
AU - Romano, Maria
AU - Salmona, Mario
AU - Ciaccia, Adalberto
AU - Fabbri, Leonardo Michele
AU - Mapp, Cristina Elisabetta
PY - 1996
Y1 - 1996
N2 - Objectives - In a previous study on bronchoalveolar lavage fluid from rats exposed in vivo for seven days to 10 ppm nitrogen dioxide (NO 2), it has been shown that there is an influx of macrophages into the airways. The present study investigated the effect of seven day exposure to 10 ppm NO 2, on: (a) lung tissue inflammation and morphology; (b) airway microvascular leakage; (c) in vitro contractile response of main bronchi. Methods - Lung tissue was studied by light microscopy, after fixing the lungs by inflation with 4% formalin at a pressure of 20 cm H 2O. Microvascular leakage was measured by extravasation of Evans blue dye in the larynx, trachea, main bronchi, and intrapulmonary airways. Smooth muscle responsiveness was evaluated by concentration-response curves to acetylcholine (10 -9-10 -3 M), serotonin (10 -9-10 -4 M), and voltage-response curves (12-28 V) to electrical field stimulation. Results - Histology showed an increased total inflammation at the level of respiratory bronchioles and alveoli. No influx of inflammatory cells was found in the main bronchi. A loss of cilia in the epithelium of small airways and ectasia of alveolar capillaries was also found. By contrast, no alterations to microvascular permeability or modification of bronchial smooth muscle responsiveness was found. Conclusions - Subchronic exposure to 10 ppm NO 2 causes airway inflammation and structural damage, but does not cause any persistent alteration to microvascular permeability or bronchial smooth muscle responsiveness in rats.
AB - Objectives - In a previous study on bronchoalveolar lavage fluid from rats exposed in vivo for seven days to 10 ppm nitrogen dioxide (NO 2), it has been shown that there is an influx of macrophages into the airways. The present study investigated the effect of seven day exposure to 10 ppm NO 2, on: (a) lung tissue inflammation and morphology; (b) airway microvascular leakage; (c) in vitro contractile response of main bronchi. Methods - Lung tissue was studied by light microscopy, after fixing the lungs by inflation with 4% formalin at a pressure of 20 cm H 2O. Microvascular leakage was measured by extravasation of Evans blue dye in the larynx, trachea, main bronchi, and intrapulmonary airways. Smooth muscle responsiveness was evaluated by concentration-response curves to acetylcholine (10 -9-10 -3 M), serotonin (10 -9-10 -4 M), and voltage-response curves (12-28 V) to electrical field stimulation. Results - Histology showed an increased total inflammation at the level of respiratory bronchioles and alveoli. No influx of inflammatory cells was found in the main bronchi. A loss of cilia in the epithelium of small airways and ectasia of alveolar capillaries was also found. By contrast, no alterations to microvascular permeability or modification of bronchial smooth muscle responsiveness was found. Conclusions - Subchronic exposure to 10 ppm NO 2 causes airway inflammation and structural damage, but does not cause any persistent alteration to microvascular permeability or bronchial smooth muscle responsiveness in rats.
KW - airway smooth muscle
KW - lung histology
KW - vascular permeability
UR - http://www.scopus.com/inward/record.url?scp=8944244524&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=8944244524&partnerID=8YFLogxK
M3 - Article
C2 - 8758032
AN - SCOPUS:8944244524
VL - 53
SP - 379
EP - 386
JO - Occupational and Environmental Medicine
JF - Occupational and Environmental Medicine
SN - 1351-0711
IS - 6
ER -