HYPERBARIC-OXYGEN PRETREATMENT ATTENUATES HEPATIC REPERFUSION INJURY

Microcirculatory derangement, energy depletion and lipid peroxidation have been related to development of ischemia-reperfusion injury in the liver. This study investigates the effects of hyperbaric oxygen (HBO) on hepatic ischemia-reperfusion injury. Adult, male Sprague-Dawley ra ts were used. Three groups were evaluated: 1) sham-operated control (l aparotomy only, no ischemia, no HBO), n=8; 2) ischemia control(l-h isc hemia, 2-h reperfusion, no HBO), n=8; and 3) HBO pretreatment (100% ox ygen, 2.5 atm absolute, 90 min) plus ischemia (l-h ischemia, 2-h reper fusion), n=8. An in vivo microscope was used to investigate hepatic mi crocirculation. Tissue malondialdehyde (MDA) and adenosine triphosphat e (ATP) were determined. In comparison with the ischemia control group , HBO significantly improved harmful insults following ischemia-reperf usion. HBO lessened adherent leukocyte count (6.00+/-1.31 cells/200 mu m vs 11.38+/-2.88 cells/200 mu m), and improved flow velocity (1.72+/ -0.26 mm/s vs 0.83+/-0.19 mm/s) in post-sinusoidal venules. HBO also r educed MDA (1.04+/-0.24 nmol/mg protein vs 2.24+/-0.49 mu mol/g protei n), and increased ATP (2.03+/-0.17 mu mol/g wet wt vs 0.73+/-0.11 mu m ol/g wet wt) levels. This study demonstrates that HBO before ischemia may ameliorate the ischemia-reperfusion injury of the liver in the rat model.