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- Title
Effects of Dexamethasone on Functional and Pathological Changes in Rat Bronchi Caused by High Acute Exposure to Chlorine.
- Authors
Demnati, R.; Fraser, R.; Martin, J. G.; Plaa, G.; Malo, J. L.
- Abstract
We assessed the effects of dexamethasone on functional and histological changes after acute exposure to a high level of chlorine gas in an animal model of reactive airways dysfunction syndrome (RADS). Sprague-Dawley male rats were exposed to 1500 ppm of chlorine for 5 min and treated with either dexamethasone (dex; 300 μg/kg/day) or saline intraperitoneally for 7 days. Lung resistance (RL), airway responsiveness to inhaled methacholine (MCh), airway wall morphometric measurements, and bronchoalveolar lavage (BAL) cells were assessed over a 2-week period after exposure. Dex administration significantly attenuated both chlorine-induced increased RL, and chlorine-induced increased responsiveness to methacholine compared with saline: −2.7 ± 6.8% vs 102.3 ± 36.6% change from baseline RL (P < 0.01) and 2.5 ± 0.6 mg/ml vs 1.2 ± 0.7 mg/ml in the MCh concentration required to double the RL from baseline (P < 0.01). There was a tendency, albeit nonsignificant, for improvement in some indices of epithelial injury. Dex significantly attenuated the postexposure neutrophilic cellular response in BAL 1 day after exposure (15.8 ± 4.9% neutrophils in the dex group vs 49.8 ± 2.7% neutrophils in the saline group) (P 5≤0.001). Our results show that dex administration helps maintain pulmonary function, reduces BAL inflammatory cell number, and tends to improve some morphometric airway wall structure parameters in rats exposed to chlorine.
- Publication
Toxicological Sciences, 1998, Vol 45, Issue 2, p242
- ISSN
1096-6080
- Publication type
Article
- DOI
10.1006/toxs.1998.2532