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Dexamethasone inhibits leukocyte emigration in rat mesenteric post‐capillary venules: an intravital microscopy study
Author(s) -
Tailor Anitaben,
Flower Roderick J.,
Perretti Mauro
Publication year - 1997
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.62.3.301
Subject(s) - dexamethasone , intravital microscopy , extravasation , endocrinology , medicine , ed50 , biology , platelet activating factor , vascular permeability , immunology , microcirculation , in vitro , biochemistry
The effect of subcutaneous administration of dexamethasone (DEX) on interleukin‐lβ (IL‐lβ, 20 ng i.p., – 2 h) and platelet‐activating factor (PAF, 100 nM in superfusion) ‐induced leukocyte interaction with the endothelium of rat mesenteric post‐capillary venules was studied. DEX produced a dose‐dependent inhibition of IL‐lβ‐induced leukocyte extravasation in the rat mesenteric vascular bed, with a calculated ED 50 of 40 μg/kg and a maximal effect of 80–100% inhibition at 0.1 mg/kg. IL‐lβ‐induced cell adhesion to post‐capillary venules was only partially inhibited by the steroid, with a calculated ED 50 of 480 μg/kg and a maximal effect of 40–60% inhibition. Furthermore, the steroid inhibited leukocyte emigration, but not adhesion, caused by superfusion of the mesenteric vascular bed with PAF. A doubling of leukocyte emigration time (from 226 to 552 s) was observed after treatment of rats with DEX. Administration for 5 days of a dose of 10 μg/kg DEX (which was inactive when given as a single injection) resulted again in a selective inhibition of IL‐lβ‐induced leukocyte emigration, without effect on cell adhesion. These data demonstrate a preferential susceptibility of the leukocyte emigration process to the inhibitory action of DEX. J. Leukoc. Biol. 62: 301–308; 1997.