A PAF antagonist blocks antigen-induced airway hyperresponsiveness and inflammation in sheep

M. Soler, M. W. Sielczak, W. M. Abraham

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

We studied the effects of WEB-2086, a specific antagonist of platelet-activating factor (PAF), on the development of antigen-induced airway hyperresponsiveness and inflammation in sheep (n=8). For these studies, airway responsiveness was determined from slopes of carbachol dose-response curves (DRC) performed at base line (prechallenge) and 2 h after Ascaris suum antigen challenges in the following three protocols: 1) antigen challenge alone (control trial), 2) WEB-2086 (1 mg/kg iv) given 30 min before antigen challenge (WEB pretreatment), and 3) WEB-2086 given 2 h after antigen challenge, immediately before the postchallenge DRC (WEB posttreatment). Airway inflammation was assessed by bronchoalveolar lavage (BAL) before antigen challenge and after the postchallenge DRC for each trial. A. suum challenge resulted in acute increases in specific lung resistance that were not different among the three trials. Antigen challenge (control trial) caused a 93% increase (P < 0.05) in the slope of the carbachol DRC when compared with the prechallenge value. WEB pretreatment (1 mg/kg) reduced (P < 0.05) this antigen-induced hyperresponsiveness, whereas pretreatment with a 3-mg/kg dose completely prevented it. WEB posttreatment was ineffective in blocking this hyperresponsiveness. BAL neutrophils increased after antigen challenge in the control trial and when WEB-2086 was given after antigen challenge (P < 0.05). Pretreatment with WEB-2086 (1 or 3 mg/kg) prevented this neutrophilia. This study provides indirect evidence for antigen-induced PAF release in vivo and for a role of endogenous PAF in the modulation of airway responsiveness and airway inflammation after antigen-induced bronchoconstriction in sheep.

Original languageEnglish (US)
Pages (from-to)406-413
Number of pages8
JournalJournal of applied physiology
Volume67
Issue number1
DOIs
StatePublished - 1989

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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