We studied the effect of dexamethasone on microvascular leakage (using Evans blue dye as a marker of plasma exudation) induced in rat airways by platelet-activating factor (PAF). Intravenously administered PAF caused a dose-related increase in plasma leakage over the range 0.1 to 1 micrograms/kg. At 500 ng/kg PAF, the response was maximal in the extrapulmonary airways examined with increases in leakage above those in control animals of 312% in the larynx, 295% in the trachea, and 167% in the main bronchi. A maximal response was not achieved in the intrapulmonary airways at the doses of PAF tested: at 1 microgram/kg the increase was 206% above that in control animals. Dexamethasone, given by intraperitoneal injection 24 h and 4 h before PAF at a dose of 0.2 mg/kg on each occasion, partially inhibited leakage induced by PAF (1 microgram/kg) in all airway levels studied by 43 to 65%. At each level the tissue concentration of dye was reduced to a value that was significantly (p less than 0.05) different from either PAF or control values. We also determined whether a high dose (8 mg/kg) of dexamethasone given intraperitoneally would inhibit plasma leakage of dye induced by either PAF or antigen-challenge of sensitized rats. When given 4 h before antigen, dexamethasone completely prevented allergen-induced leakage in the airways showing significant leakage (larynx, trachea, and intrapulmonary airways). Similarly, dexamethasone (4 h before) partially inhibited PAF-induced leakage in the trachea and main bronchi. In summary, in rat airways, both low and high doses of dexamethasone markedly inhibit mediator-induced plasma exudation.
Corticosteroid inhibition of airway microvascular leakage / P., Boschetto; D. F., Rogers; Fabbri, Leonardo; P. J., Barnes. - In: AMERICAN REVIEW OF RESPIRATORY DISEASE. - ISSN 0003-0805. - STAMPA. - 143(1991), pp. 605-609.
|Data di pubblicazione:||1991|
|Titolo:||Corticosteroid inhibition of airway microvascular leakage.|
|Autore/i:||P., Boschetto; D. F., Rogers; Fabbri, Leonardo; P. J., Barnes|
|Codice identificativo ISI:||WOS:A1991FA93100027|
|Codice identificativo Scopus:||2-s2.0-0025971576|
|Codice identificativo Pubmed:||2001074|
|Citazione:||Corticosteroid inhibition of airway microvascular leakage / P., Boschetto; D. F., Rogers; Fabbri, Leonardo; P. J., Barnes. - In: AMERICAN REVIEW OF RESPIRATORY DISEASE. - ISSN 0003-0805. - STAMPA. - 143(1991), pp. 605-609.|
|Tipologia||Articolo su rivista|
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