Protective effect of low dose of ascorbic acid on hepatobiliary function in hepatic ischemia/reperfusion in rats

Background/Aims: The aim of this study was to investigate the effect of ascorbic acid (AA) an alterations in hepatic secretory and microsomal functions during hepatic ischemia and reperfusion. Methods: Rats were subjected to 60 min of hepatic ischemia, and 1 and 5 h of reperfusion. Five minutes prior to ischemia, the animals were administered either vehicle or ascorbic acid (AA) (30, 100, 300, and 1000 mg/kg) intravenously. Results: The serum aminotransferase level and lipid peroxidation were markedly higher as a result of ischemia/ reperfusion. These increases were significantly attenuated by AA doses of 30 and 100 mg/kg but were augmented by dose of 1000 mg/kg. Bile flow and cholate output were markedly, decreased by ischemia/reperfusion. AA doses of 30 and 100 mg/kg restored but dose of 1000 mg/kg inhibited their secretion. Both the cytochrome P-450 content and aminopyrine N-demethylase activity were decreased by ischemia/reperfusion, which were prevented by AA doses of 30 and 100 mg/ kg but were aggravated by dose of 1000 mg/kg. Aniline p-hydroxylase activity was elevated by ischemia/reperfusion, and this was prevented by AA doses of 100, 300 and 1000 mg/kg. Conclusions: Ischemia/reperfusion diminishes the hepatic secretory and microsomal functions. AA has both antioxidant and pro-oxidant effects, depending upon the dose. (C) 2002 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.