3-nitrotyrosine and Lung-Diseases--Obstructive

To determine concentrations of nitric oxide (NO) in plasma and bronchoalveolar lavage fluid (BALF) and localize nitric oxide synthesis in the lungs of horses with summer pasture-associated obstructive pulmonary disease (SPAOPD).. 7 adult horses with SPAOPD and 6 clinically normal adult horses.. Severity of SPAOPD was determined by use of clinical scores, change in intrapleural pressure (APpl) during tidal breathing, cytologic analysis of BALF, and histologic evaluation of lung specimens obtained during necropsy. Nitric oxide concentrations in plasma, BALF and epithelial lining fluid (ELF) were determined by use of a chemiluminescent method. Inducible nitric oxide synthase (iNOS) and nitrotyrosine (NT) were localized in formalin-fixed lung specimens by use of immunohistochemical staining, and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) activity was localized in cryopreserved specimens by use of histochemical staining.. Plasma concentration of NO in affected horses was slightly but not significantly greater than concentration in nonaffected horses. Nitric oxide concentrations in BALF or ELF did not differ between groups. Immunoreactivity of iNOS in bronchial epithelial cells of 3 of 5 lung lobes was greater in horses with SPAOPD, compared with nonaffected horses. However, staining for NT and NADPHd activity did not differ between groups.. Expression of iNOS was greater in bronchial epithelial cells of horses with SPAOPD, compared with nonaffected horses, suggesting that NO may play a role in amplifying the inflammatory process in the airways of horses with this disease.

Topics: Animals; Bronchi; Bronchoalveolar Lavage Fluid; Epithelium; Female; Horse Diseases; Horses; Immunohistochemistry; Lung Diseases, Obstructive; Male; NADPH Dehydrogenase; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Tyrosine

Peroxynitrite, nitrogen dioxide, and other reactive nitrogen species (RNS) that are formed in the reaction of nitric oxide (NO) with superoxide anion, and in peroxidase-dependent mechanisms, have a potent inflammatory action. These molecules may therefore increase in number and have a role in inflammatory airway diseases. In the present study, we quantified RNS using immunostaining of nitrotyrosine and inducible NO synthase (iNOS) in airway inflammatory cells obtained by the induced sputum technique, and also quantified the exhaled NO concentration in subjects with chronic obstructive pulmonary disease (COPD), subjects with asthma, and healthy subjects (HS). Immunoreactivity for iNOS observed in the airway inflammatory cells was significantly and similarly higher in subjects with COPD and asthma than in HS, although exhaled NO levels were increased only in subjects with asthma. Inflammatory cells showed obvious nitrotyrosine immunoreactivity in subjects with COPD and to a lesser extent in those with asthma, but not in HS. There was a significant negative correlation between the percent predicted values of FEV(1) and the amount of nitrotyrosine formation in subjects with COPD, but not in those with asthma and HS. These results suggest that: (1) RNS may be involved in the pathobiology of the airway inflammatory and obstructive process in COPD; and (2) NO produced in the airways, presumably via iNOS, is consumed by its reaction with superoxide anion and/or peroxidase-dependent mechanisms.

Topics: Adult; Asthma; Cell Count; Female; Forced Expiratory Volume; Humans; Immunohistochemistry; Lung; Lung Diseases, Obstructive; Male; Middle Aged; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Sputum; Tyrosine