Abstract | BACKGROUND: Polymorphoneutrophils (PMNs) are activated by inflammatory mediators following splanchnic ischemia/reperfusion (I/R), potentially injuring organs such as the lung. As a result, some patients develop respiratory failure following abdominal aortic aneurysm repair. Pulmonary cyclooxygenase (COX)-2 protects against acid aspiration and bacterial instillation via lipoxins, a family of potent anti-inflammatory lipid mediators. We explored the role of COX-2 and lipoxin A(4) in experimental I/R-mediated lung injury. MATERIALS AND METHODS: Sprague-Dawley rats were assigned to one of the following five groups: (1) controls; (2) aortic cross-clamping for 45 min and reperfusion for 4 h (I/R group); (3) I/R and SC236, a selective COX-2 inhibitor; (4) I/R and aspirin; and (5) I/R and iloprost, a prostacyclin (PGI(2)) analogue. Lung injury was assessed by wet/dry ratio, myeloperoxidase (MPO) activity, and bronchoalveolar lavage (BAL) neutrophil counts. BAL levels of thromboxane, PGE(2), 6-keto-PGF(1)α (a hydrolysis product of prostacyclin), lipoxin A(4), and 15-epi-lipoxin A(4) were analyzed by enzyme immunoassay (EIA). Immunostaining for COX-2 was performed. RESULTS: I/R significantly increased tissue MPO, the wet/dry lung ratio, and neutrophil counts. These measures were significantly further aggravated by SC236 and improved by iloprost. I/R increased COX-2 immunostaining and both PGE(2) and 6-keto-PGF(1α) levels in BAL. SC236 markedly reduced these prostanoids and lipoxin A(4) compared with I/R alone. Iloprost markedly increased lipoxin A(4) levels. The deleterious effect of SC236 and the beneficial effect of iloprost was associated with a reduction and an increase, respectively, in lipoxin A(4) levels. CONCLUSIONS:
Lipoxin A(4) warrants further evaluation as a mediator of COX-2 regulated lung protection.
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Authors | Michael Scully, Chen Gang, Claire Condron, David Bouchier-Hayes, Anthony J Cunningham |
Journal | The Journal of surgical research
(J Surg Res)
Vol. 175
Issue 1
Pg. 176-84
(Jun 01 2012)
ISSN: 1095-8673 [Electronic] United States |
PMID | 21944479
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2012. Published by Elsevier Inc. |
Chemical References |
- 4-(5-(4-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl)benzenesulfonamide
- Cyclooxygenase 2 Inhibitors
- Lipoxins
- Protective Agents
- Pyrazoles
- Sulfonamides
- lipoxin A4
- Cyclooxygenase 2
- Iloprost
- Aspirin
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Topics |
- Animals
- Aspirin
(pharmacology)
- Cyclooxygenase 2
(metabolism)
- Cyclooxygenase 2 Inhibitors
(pharmacology)
- Disease Models, Animal
- Iloprost
(pharmacology)
- Lipoxins
(metabolism)
- Lung
(drug effects)
- Lung Injury
(metabolism, physiopathology, prevention & control)
- Male
- Protective Agents
(pharmacology)
- Pyrazoles
(pharmacology)
- Rats
- Rats, Sprague-Dawley
- Reperfusion Injury
(metabolism, physiopathology, prevention & control)
- Sulfonamides
(pharmacology)
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