| Autor: |
O'Leary EC; Cardiovascular Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA., Zuckerman SH |
| Jazyk: |
angličtina |
| Zdroj: |
American journal of respiratory cell and molecular biology [Am J Respir Cell Mol Biol] 1997 Mar; Vol. 16 (3), pp. 267-74. |
| DOI: |
10.1165/ajrcmb.16.3.9070611 |
| Abstrakt: |
In an intratracheal endotoxin lipopolysaccharide (LPS) challenge model of acute lung injury, we recently reported that while dexamethasone (DEX) at 2 to 4 mg/kg reduced neutrophil (PMN) emigration into the airways, bronchoalveolar lavage (BAL) fluid contained substantial amounts of immunoreactive macrophage inflammatory protein-2 (MIP-2). In the present study, DEX in quantities up to 30 mg/kg further reduced PMN influx, but MIP-2 levels were unaffected 3 h following LPS challenge. MIP-2 in 3-h BAL samples from DEX- or vehicle-pretreated animals was bioactive and approximately 75% of the ex vivo chemotactic activity was neutralized by polyclonal antirat MIP-2. In contrast to the in vivo studies, DEX significantly suppressed MIP-2 synthesis from LPS-stimulated rat alveolar macrophages in vitro. Ex vivo chemotactic activity was comparable between BAL samples from DEX- and vehicle-pretreated rats. Chemotaxis of rat PMN to recombinant MIP-2 exhibited a bell-shaped concentration-response profile in vitro with optimal activity at 17.6 ng/ml and this was shifted 16-fold to the right by antirat MIP-2. Three-hour BAL MIP-2 (10.73 +/- 0.45 ng/ml) correlated with the ascending limb of the recombinant rat MIP-2 concentration-response profile. In addition to inhibiting chemotaxis, antirat MIP-2 also reduced the chemokinetic response to 3-h BAL fluid by 84%. The present study demonstrates that in vivo MIP-2 is bioactive, and because its synthesis within the rat lung is resistant to DEX it is likely to play a significant role in glucocorticoid refractory PMN influx within the airways during acute lung injury. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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