Acute lung injury in a rat model of intestinal ischemia-reperfusion: the potential time depended role of phospholipases A(2).
BACKGROUND
A pivotal role of phospholipase A(2) (PLA(2)) and platelet-activating factor-acetylhydrolase (PAF-AcH) as enzymes involved in lung inflammation has recently been suggested. The objective of this study was to elucidate the role and the time dependence of PLA(2) and PAF-AcH fluctuations in the lung relative to the evolution of intestinal ischemia-reperfusion (IIR).


METHODS
Rats were randomly allocated to five groups of IIR induced by occlusion of the superior mesenteric artery for 45 min followed by 1 min, 2, 4, and 8 h of reperfusion (expGroups) and five corresponding sham groups (sGroups). Bronchoalveolar lavage fluid was obtained from the right lung and its biochemical (protein, PLA(2), PAF-AcH) and cytological characteristics were determined. Plasma malonyldialdehyde was measured as a marker of lipid peroxidation. The 4 and 8 h reperfusion expGroups had significantly (P < 0.05) elevated alveolar-arterial O(2) gradient values compared with the corresponding controls. Total protein, PLA(2) and PAF-AcH levels significantly (P < 0.05) increased in expGroups compared with the corresponding shams after 4 h of reperfusion. Total bronchoalveolar lavage fluid cells and plasma malonyldialdehyde were significantly (P < 0.05) elevated in expGroups compared with the sGroups after 2 h of reperfusion.


CONCLUSIONS
PLA(2) could act synergistically or parallel with the reactive oxygen species produced during IIR, resulting in the induction or even in the exacerbation of the inflammatory reaction in acute respiratory distress syndrome. PAF-AcH could play an anti-inflammatory role by reducing the concentration of PAF.
Kostopanagiotou
Georgia
G
2nd Department of Anesthesiology, Medical School, University of Athens, Attikon Hospital, Chaidari, Greece.
Avgerinos
Efthimios
E
Costopanagiotou
Constantinos
C
Arkadopoulos
Nikolaos
N
Andreadou
Ioanna
I
Diamantopoulou
Kalliopi
K
Lekka
Marilena
M
Smyrniotis
Vassilios
V
Nakos
George
G
D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000502:physiology*; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D004195:Disease Models, Animal; D007422:Intestines / Q000098:blood supply*; D008168:Lung / Q000473:pathology; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D054467:Phospholipases A2 / Q000502:physiology*; D010972:Platelet Activating Factor / Q000502:physiology; D011659:Pulmonary Gas Exchange; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D015427:Reperfusion Injury / Q000209:etiology*; D012128:Respiratory Distress Syndrome / Q000209:etiology*; D013997:Time Factors
D010972:Platelet Activating Factor; D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D054467:Phospholipases A2; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase