The role of intermittent hepatic pedicle clamping on oxygen-derived free radical generation in the rat liver

Sim, Mun Sup; Kim, Dong Heon; Baik, Seong Wan; Shin, Sang Wook; Kim, Hae Young; Jeon, Tae Yong; Jo, Hong Jae

Abstract

BACKGROUND/AIMS: The tolerance of the liver to ischemia during intermittent hepatic pedicle clamping was compared with that during continuous hepatic pedicle clamping, and intermittent hepatic pedicle clamping was thought to more tolerable to ischemia/reperfusion injury. The mechanisms underlying this were unknown. We examined the relationship between ischemia/reperfusion injury and the production of oxygen-derived free radicals using spin resonance spectrometry.
METHODS
Adult male Sprague-Dawley rats were subjected to either continuous or intermittent hepatic pedicle clamping. Alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone was administered to rats as a spin trap agent. Continuous clamping (15, 30, or 60 minutes) or intermittent clamping(four cycles of 15-minutes ischemia and 5 or 15 minutes of reperfusion) of hepatic pedicle was carried out. After reperfusion, blood samples were obtained and measuring liver enzyme to evaluate hepatic injury. Hepatic tissue blood flow was measured using a color Doppler blood flowmeter.
RESULTS
When there was a longer period of hepatic pedicle occlusion, increased oxygen-derived free radical generation was detected after reperfusion. There was no significant increase in oxygen-derived free radical production or liver enzymes leakage when the duration of ischemia was 15 minutes. Oxygen-derived free radical generation and liver enzyme leakage were significantly less in intermittent pedicle clamping than in continuous clamping for 60 minutes.
CONCLUSION
According this results, there is a oxygen-derived free radicals and liver damage in less in intermittent pedicle clamping than continuous clamping although many oxygen-derived free radicals are produced.