Early physiological and biological features in three animal models of induced acute lung injury.
BACKGROUND
Critically ill patients often develop acute lung injury (ALI) in the context of different clinical conditions. We aimed to explore differences in early local and systemic features in three experimental animal models of ALI.


METHODS
Mechanically ventilated male Sprague-Dawley rats were randomized to high tidal volume (VT) ventilation (HVT) (n = 8, VT 24 ml/kg), massive brain injury (MBI) (n = 8, VT 8 ml/kg) or endotoxemia (LPS) (n = 8, VT 8 ml/kg). Each experimental group had its own control group of eight rats (VT 8 ml/kg). We measured arterial blood gases, mean arterial pressure, lung compliance, inflammatory mediators in plasma and their expression and gelatinase activity in the lungs after 3 h of injury.


RESULTS
Despite maintaining relatively normal lung function without evidence of important structural changes, we observed altered lung and systemic inflammatory responses in all three experimental models. LPS triggered the most robust inflammatory response and HVT the lowest systemic proinflammatory response. The HVT group had higher Il6, Tnf and Cxcl2 mRNA in lungs than MBI animals. Metalloproteinase activity/expression and neutrophilic recruitment in the lungs were higher in HVT than in LPS or MBI.


CONCLUSIONS
The early responses to direct or remote lung insult in our three models of ALI captured different physiological and biological features that could lead to respiratory and/or multiorgan failure.
Critical Care Center, Hospital de Sabadell, Corporació Parc Taulí, Institut Universitari, Esfera UAB, Parc Taulí s/n, 08208 Sabadell, Spain. jlopeza@tauli.cat
Josefina
J
López-Aguilar
María Elisa
ME
Quilez
Octavi
O
Martí-Sistac
Carolina
C
García-Martín
Gemma
G
Fuster
Ferranda
F
Puig
Carlos
C
Flores
Jesús
J
Villar
Antonio
A
Artigas
Lluís
L
Blanch
D000208:Acute Disease; D000818:Animals; D001930:Brain Injuries / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology*; D004195:Disease Models, Animal; D019446:Endotoxemia / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D008070:Lipopolysaccharides / Q000378:metabolism; D008297:Male; D045726:Metalloproteases / Q000378:metabolism; D011175:Positive-Pressure Respiration; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012121:Respiration, Artificial; D012720:Severity of Illness Index; D013997:Time Factors
D008070:Lipopolysaccharides; D045726:Metalloproteases