[The role of Ca(2+)-ATPase and oxygen radical in reperfusion injury of rat liver].

The effects of ischemia and reperfusion with and without oxygen radical scavengers and xanthine oxidase inhibitors on Ca(2+)-ATPase activity were examined in the rat liver of 5 min ischemia followed by 5 and 10 min reperfusion. Ischemia was produced by the ligation of right hepatic artery and right portal vein. Superoxide dismutase, catalase and allopurinol were administered by subcutaneous injection of 60,000U/kg, 90,000U/kg and 200mg/kg, respectively before ligation. Reaction products of Ca(2+)-ATPase were morphometrically analyzed by RUZEX IIIU. Histochemically, Ca(2+)-ATPase activities were demonstrated on plasma membrane of liver cells, bile canaliculi and Kupffer cells involving mitochondria in liver cells of control rats. Ca(2+)-ATPase activities were depressed in the central lobes of liver after 5 min ischemia followed by 5 and 10min reperfusion. However, the activities of Ca(2+)-ATPase were not depressed by addition of oxygen radical scavengers and xanthine oxidase inhibitor before ischemia. These results suggest that oxygen free radicals may influence Ca(2+)-ATPase activity and contribute to liver cell damage due to ischemia-reperfusion.