Deep hypothermia impact on acid-base parameters and liver antioxidant status in an in vivo rat model.
Although clinical hypothermia is used for reducing postischemic damage, injurious effects have also been reported. To determine whether hypoxia and oxidative stress are induced by systemic deep hypothermia, we used an in vivo rat model keeping the arterial Pco2 constant. Animals were divided into 4 groups: sham, 2 h deep hypothermia (21 degrees C), 1 h posthypothermia (rewarmed to 37 degrees C after 2 h deep hypothermia), and 3 h normothermia. Blood gases, portal vein blood flow, arterial pressure, and heart rate were monitored throughout the experiment. Liver enzyme antioxidant activity was also examined. The hemodynamic parameters decreased drastically during hypothermia, but were fully restored after rewarming. No changes in hepatic antioxidant activity (catalase, glutathione peroxidase, and superoxide dismutase) were observed. The redox level in liver (GSH/GSSG ratio) was preserved in hypothermia but decreased when animals were rewarmed. ALT did not increase and no evidence of tissue hypoxia was detected in liver regarding the restricted flow during hypothermia. With the described protocol, deep hypothermia is regarded as an experimental safe model.
Alva
Norma
N
Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, E-08028 Barcelona, Spain. nvalva@ub.edu
Carbonell
Teresa
T
Palomeque
Jesús
J
D000136:Acid-Base Equilibrium / Q000502:physiology*; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001775:Blood Circulation; D001784:Blood Gas Analysis; D001794:Blood Pressure; D001831:Body Temperature; D002245:Carbon Dioxide / Q000097:blood; D015687:Cell Hypoxia; D007036:Hypothermia, Induced / Q000009:adverse effects; D019344:Lactic Acid / Q000378:metabolism; D008099:Liver / Q000098:blood supply / Q000201:enzymology* / Q000473:pathology; D008297:Male; D010084:Oxidation-Reduction; D010100:Oxygen / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D017694:Rewarming / Q000009:adverse effects
D000975:Antioxidants; D017382:Reactive Oxygen Species; D002245:Carbon Dioxide; D019344:Lactic Acid; D000410:Alanine Transaminase; D010100:Oxygen