Effect of intratracheal dexamethasone on oleic acid-induced lung injury in the rat.

The therapeutic efficacy of single-dose intratracheal dexamethasone (2.5 mg/kg) in oleic acid-induced acute lung injury in the rat was established by showing significant improvement in bronchoalveolar lavage parameters and lung compliance at 24 h after oleic acid as compared with animals not treated with oleic acid. An equivalent dose of intraperitoneal dexamethasone demonstrated no therapeutic benefit at 24 h after oleic acid. The therapeutic effect of this single-dose intratracheal dexamethasone regimen was accompanied by recovery to normal bronchoalveolar parameters and lung compliance at 7 days, in contrast to previous observations made with high-dose sustained intraperitoneal dexamethasone (4 mg/kg for 7 days). This improved benefit:toxicity ratio of intratracheal dexamethasone compared with systemic dexamethasone may be due to enhanced topical anti-inflammatory potency relative to systemic potency and toxicity.