Evidence that arachidonic acid derived from neutrophils and prostaglandin E2 are associated with the induction of acute lung inflammation by lipopolysaccharide of Escherichia coli.
OBJECTIVE
The involvement of arachidonic acid (AA) and PGE2 during the E. coli lipopolysaccharide (LPS)-induced acute lung injury was investigated.


METHODS
Adult male Wistar rats were used. For in vitro studies, rat neutrophils, bronchoalveolar lavage (BAL) fluid, and lug vascular endothelium were used, as described below.


METHODS
Rats were given an intratracheal injection of LPS (750 microg).


METHODS
Total and differential cell counts in BAL fluid; enzyme-linked immunoassay (ELISA) analyses of TNF-alpha, IL-1beta, LTB4 and PGE2 in BAL, and immunohistochemical detection of ICAM-1 on lung vascular endothelium were performed six h after LPS challenge. Fatty acid composition of blood neutrophils and plasma was analyzed by HPLC.


RESULTS
Rats instilled with LPS presented a sixty three-fold increase in the number of neutrophils in BAL (from 0.5 x 10(6) to 31.5 x 10(6) cells), accompanied by increased levels of TNF-alpha and IL-1beta (p < 0.001), and a three-fold increase in ICAM-1 expression on vascular endothelium. The content of AA in blood neutrophils was reduced by 50%, whereas the level of PGE2 in BAL was increased by 3.5 fold, without changes in the levels of LTB4.


CONCLUSIONS
These findings suggest that AA and PGE2 are associated with LPS challenge.
Alba-Loureiro
T C
TC
Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1524, 05508-900, São Paulo, SP, Brazil. tatica@fisio.icb.usp.br
Martins
E F
EF
Miyasaka
C K
CK
Lopes
L R
LR
Landgraf
R G
RG
Jancar
S
S
Curi
R
R
Sannomiya
P
P
D000208:Acute Disease; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D015232:Dinoprostone / Q000378:metabolism*; D004926:Escherichia coli; D007150:Immunohistochemistry; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007375:Interleukin-1 / Q000378:metabolism; D007958:Leukocyte Count; D007975:Leukotriene B4 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D009504:Neutrophils / Q000378:metabolism*; D011014:Pneumonia / Q000139:chemically induced* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D007375:Interleukin-1; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D007975:Leukotriene B4; D016718:Arachidonic Acid; D015232:Dinoprostone