Exhaled carbon monoxide and inducible heme oxygenase expression in a rat model of postperfusion acute lung injury.
OBJECTIVE
Expression of inducible heme oxygenase has been shown to be increased in various visceral inflammatory disorders, which may confer a protective role. The purpose of our study was to determine whether the expression of inducible heme oxygenase was up-regulated within lungs in a rat model of extracorporeal circulation.


METHODS
Wistar rats underwent either a partial femoro-femoral extracorporeal circulation in normothermia for 3 hours (n = 5) or a sham procedure (n = 5). Exhaled carbon monoxide concentration was monitored with an infrared analyzer. After the rats were killed, lungs were harvested for determination of heme oxygenase activity and inducible heme oxygenase expression (by Western blot and immunohistochemistry). Lung injury was also assessed by arterial blood gas analysis and microscopic study.


RESULTS
Extracorporeal circulation was responsible for a lung injury characterized by decreased arterial blood oxygen saturation and typical morphologic findings (marked alveolar neutrophil infiltration; interstitial edema). Exhaled carbon monoxide concentration remained stable throughout the experiment in all sham rats, whereas it increased after extracorporeal circulation (from 0.16 +/- 0.05 ppm at baseline to 0.7 +/- 0.2 ppm at end of experiment; P =.0001). Pulmonary heme oxygenase activity and inducible heme oxygenase content (assessed by Western blot) were increased within lungs of rats that underwent extracorporeal circulation. Immunohistochemistry revealed that the expression of inducible heme oxygenase was mainly localized to inflammatory cells.


CONCLUSIONS
Post-extracorporeal circulation acute lung injury in rats was associated with an increased expression of inducible heme oxygenase, the functional significance of which remains to be determined.
Zegdi
Rachid
R
Laboratoire d'Etudes des Greffes et Prothèses Cardiaques, Hôpital Broussais, Paris, France. rzegdi@hotmail.com
Fabre
Olivier
O
Lila
Nermine
N
Fornès
Paul
P
Cambillau
Michèle
M
Shen
Ming
M
Hervé
Philippe
P
Carpentier
Alain
A
Fabiani
Jean-Noël
JN
D000208:Acute Disease; D000818:Animals; D015153:Blotting, Western; D001944:Breath Tests; D002248:Carbon Monoxide / Q000032:analysis*; D005112:Extracorporeal Circulation; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D051547:Heme Oxygenase-1; D007150:Immunohistochemistry; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000209:etiology / Q000378:metabolism*; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D015854:Up-Regulation
D002248:Carbon Monoxide; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1