Influence of Different Oxygen
Modes on the Blood Oxygen Transport and Prooxidant-Antioxidant
Status during Hepatic Ischemia/Reperfusion
V. V. ZINCHUK, M. N. KHODOSOVSKY,
D.A. MASLAKOV
Department of Physiology, Grodno Medical University, Grodno,
Belarus
Received June 24, 2002
Accepted November 5, 2002
Summary
Oxygen supply was corrected in rabbits during the hepatic
ischemia/reperfusion by means of different breathing mixtures:
hypoxic (14.8 % O2+85.2 % N2), hyperoxic (78 % O2+20.2 % N2+ 1.8
% CO2), or hypercapnic (5 % CO2 in air). Hepatic ischemia was
induced for 30 min by ligation of hepatic artery, reperfusion
period lasted 120 min. Indices of blood oxygen transport
(p50act, pCO2, pH, pO2, etc.) and prooxidant-antioxidant balance
(Schiff bases, conjugated dienes, catalase, retinol,
a-tocopherol)
were measured in the blood and liver. The severity of
reperfusion damage was evaluated by the activities of alanine
and aspartate aminotransferases (ALT, AST) in the blood. Hepatic
ischemia/reperfusion resulted in higher p50act in hepatic venous
and mixed venous blood in all experimental groups. The changes
of p50act were most marked in the hypercapnic group and were the
weakest in the hypoxic group. The rise in p50act was accompanied
by higher levels of lipid peroxidation products, ALT and AST in
blood and liver homogenates, and by a simultaneous fall of -tocopherol
and retinol concentrations, except in the hypoxic group.
Catalase activity at the end of reperfusion increased under
normoxia, decreased under hyperoxia or hypercapnia and did not
change under hypoxia. The moderate hypoxia during reperfusion
was accompanied by a better balance between the mechanisms of
reactive oxygen species production and inactivation that may be
observed by optimal changes in p50act and reduced the hepatic
damage in this pathological condition.
Key words
Hemoglobin-oxygen affinity • Hepatic ischemia • Reperfusion •
Hypoxia • Hyperoxia • Hypercapnia • Rabbits
Reprint requests
V. V. Zinchuk, Department of Physiology, Grodno Medical
University, 80 Gorki st., 230015, Grodno, Belarus, e-mail:
zinchuk@grsmi.unibel.by
|