Effects of dexamethasone on functional and pathological changes in rat bronchi caused by high acute exposure to chlorine

被引:23
作者
Demnati, R [1 ]
Fraser, R
Martin, JG
Plaa, G
Malo, JL
机构
[1] Hop Sacre Coeur, Dept Chest Med, Montreal, PQ H4J 1C5, Canada
[2] McGill Univ, Meakins Christie Labs, Montreal, PQ H3A 2T5, Canada
[3] McGill Univ, Dept Pathol, Montreal, PQ H3A 2T5, Canada
[4] Univ Montreal, Dept Pharmacol, Montreal, PQ H3C 3J7, Canada
关键词
irritant-induced asthma; reactive airways dysfunction syndrome; asthma; chlorine toxicity; corticosteroids;
D O I
10.1093/toxsci/45.2.242
中图分类号
R99 [毒物学(毒理学)];
学科分类号
100405 ;
摘要
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 mu g/kg/day) or saline intraperitoneally for 7 days. Lung resistance (R-L), 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 R-L and chlorine-induced increased responsiveness to methacholine compared with saline: -2.7 +/- 6.8% vs 102.3 +/- 36.6% change from baseline R-L (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 R-L 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 less than or equal to 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. (C) 1998 Society of Toxicology.
引用
收藏
页码:242 / 246
页数:5
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