Skip to main content
Article thumbnail
Location of Repository

Chronic lipopolysaccharide exposure on airway function, cell infiltration, and nitric oxide generation in conscious guinea pigs: Effect of rolipram and dexamethasone

By Toby J. Toward and Kenneth John Broadley


This study investigated whether a correlation between airway hyperreactivity (AHR), leukocyte influx, and nitric oxide (NO) existed in guinea pigs chronically exposed to lipopolysaccharide (LPS). The effect of the corticosteroid, dexamethasone, or phosphodiesterase-4 (PDE4) inhibitor, rolipram, on these features was studied. Airway function was measured in conscious guinea pigs (specific airways conductance) before and after single, double, or chronic (nine) LPS (30 microg x ml(-1), 1 h) exposures. Airway reactivity to inhaled histamine (1 mM, 20 s) was assessed before and at various times after LPS challenges. Leukocytes and NO metabolites were measured in bronchoalveolar lavage fluid (BALF). AHR occurred at 1 h after a single LPS challenge and was resolved by 4 h. This coincided with reduction and recovery, respectively, of BALF NO levels. The AHR and NO deficiency were extended to 4 h, after a double LPS exposure. Chronic LPS exposures, 48 h apart, initially caused persistent bronchodilations, whereas later exposures produced progressively persistent bronchoconstrictions. There was AHR 24 h after the eighth challenge. Twenty-four hours after the ninth LPS exposure, macrophages, neutrophils, eosinophils, and NO metabolites were elevated in BALF. Dexamethasone (20 mg x kg(-1) i.p.) or rolipram (1 mg x kg(-1) i.p.) prevented single and chronic LPS-induced AHR, the respective deficiency and elevation in NO metabolites, and the chronic LPS-induced leukocyte influx. Dexamethasone exacerbated, whereas rolipram reversed, the chronic LPS-induced bronchoconstrictions. This study demonstrates for the first time that chronic LPS causes persistent bronchoconstriction, neutrophilic inflammation, AHR, and NO overproduction in guinea pig airways. These rolipram-sensitive features suggest the potential of PDE4 inhibitors in airway disease

Topics: RS
Publisher: American Society for Pharmacology and Experimental Therapeutics
Year: 2001
OAI identifier: oai:
Sorry, our data provider has not provided any external links therefore we are unable to provide a link to the full text.

Suggested articles

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.