title: Nitric oxide modulates eosinophil infiltration in antigen-induced airway inflammation in rats.
abstract: The influence of nitric oxide (NO) on eosinophil infiltration into the airways was investigated in rats actively sensitized with ovalbumin. The animals were treated chronically with the NO synthase inhibitor, N omega-Nitro-L-arginine methyl ester (L-NAME; 75 mumol rat-1 day-1), for 4 weeks. Bronchoalveolar lavage was performed at 6, 24, 48 and 72 h after intratracheal injection of ovalbumin. Intratracheal challenge of the sensitized rats with ovalbumin caused a significant increase in total leucocyte infiltration in bronchoalveolar lavage fluid both 24 and 48 h post-ovalbumin injection. Neutrophils and eosinophils peaked, respectively, at 24 h (29%) and 48 h (30%) in bronchoalveolar lavage fluid whereas the mononuclear cell did not differ significantly from the counts in non-sensitized rats at any time. At both 6 and 24 h post-ovalbumin injection, the chronic treatment of the animals with L-NAME affected neither the total nor the differential leucocyte content. However, at 48 h post-ovalbumin challenge, the total cell count was reduced by approximately 48% in the L-NAME-treated animals and this was associated with a marked inhibition (81%) of the eosinophil influx. Histological examination of the lungs from these animals (48 h post-ovalbumin challenge) also showed a prominent reduction (69.5%; P < 0.05) of the eosinophil infiltration in the respiratory segments. Our results demonstrate that NO plays a pivotal role in the eosinophil infiltration in airways of actively sensitized rats.
authors.affiliation: Clinical Pharmacology Unit, São Francisco University Medical School, São Paulo, Brazil.
authors.forename: H H
authors.initials: HH
authors.lastname: Ferreira
authors.forename: E
authors.initials: E
authors.lastname: Bevilacqua
authors.forename: S M
authors.initials: SM
authors.lastname: Gagioti
authors.forename: I M
authors.initials: IM
authors.lastname: De Luca
authors.forename: R C
authors.initials: RC
authors.lastname: Zanardo
authors.forename: C E
authors.initials: CE
authors.lastname: Teixeira
authors.forename: P
authors.initials: P
authors.lastname: Sannomiya
authors.forename: E
authors.initials: E
authors.lastname: Antunes
authors.forename: G
authors.initials: G
authors.lastname: De Nucci
mesh_terms: D000818:Animals; D001249:Asthma / Q000139:chemically induced / Q000276:immunology / Q000503:physiopathology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D004791:Enzyme Inhibitors / Q000276:immunology / Q000494:pharmacology*; D004804:Eosinophils / Q000187:drug effects / Q000276:immunology / Q000473:pathology*; D006651:Histocytochemistry; D008168:Lung / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D010047:Ovalbumin / Q000276:immunology / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D010047:Ovalbumin; D019331:NG-Nitroarginine Methyl Ester