bof-4272 and Reperfusion-Injury

The peroxidation of membranous phospholipids induced by ischemia reperfusion was inhibited in Cu/Zn superoxide dismutase (SOD) overexpressing mice, suggesting a detrimental role for intracellular reactive oxygen species (ROS) in reoxygenated cell injury. To ascertain the in-vitro relevance of this hypothesis, the present study examined the participation of intracellular ROS in reoxygenation injury.. This examination was done in two experimental models: Cu/Zn-SOD transgenic (Tg) mice that underwent hypoxia-reoxygenation in vitro and normal mice pretreated with a specific inhibitor of xanthine oxidase, BOF-4272, followed by in vitro hypoxia-reoxygenation.. The release of aspartate aminotransferase (AST) and the peroxidation of phospholipids were both ameliorated in hepatocytes from the Tg mice compared with findings in hepatocytes from normal mice. Similar findings were seen in the BOF-4272-pretreated cells, in which there was a decrease in AST and phospholipid peroxides.. These results support the pivotal role of intracellular ROS generated by xanthine oxidase in reoxygenated cell injury, and suggest the viability of using an intracellular antioxidative therapy for reperfusion injury of the liver.

Topics: Adenosine Triphosphate; Animals; Aspartate Aminotransferase, Cytoplasmic; Enzyme Inhibitors; Free Radical Scavengers; Hepatocytes; In Vitro Techniques; Lipid Peroxidation; Liver; Mice; Mice, Transgenic; Models, Biological; Phosphatidylcholines; Reactive Oxygen Species; Reperfusion Injury; Superoxide Dismutase; Triazines; Xanthine Oxidase

We investigated the effects of the xanthine oxidase inhibitor, BOF-4272, on the production of cytokine-induced neutrophil chemoattractant (CINC) following reperfusion injury in rat liver. Ischemia was induced for 30 minutes by portal vein occlusion. Animals were pretreated with intravenous injection of BOF-4272 (1 mg/kg) or heparin (50 U/kg) 5 minutes before vascular clamp. Both BOF-4272 and heparin limited increases in the chemoattractant compared with nonpretreated rats. Pretreatment with BOF-4272 plus heparin resulted in an additive effect. Most cells immunostained for chemoattractant were macrophages in sinusoids. In vitro chemoattractant production by Kupffer cells isolated from animals pretreated with heparin or BOF-4272 was significantly lower than by Kupffer cells from nonpretreated animals. Expression of transcripts in liver for chemoattractant peaked 3 hours after reperfusion in nonpretreated animals, while pretreatment with heparin or BOF-4272 significantly decreased chemoattractant mRNA levels. In vitro chemoattractant transcription and production could be induced in naive Kupffer cells by hypoxanthine and xanthine oxidase, but BOF-4272 prevented these increases. We conclude that Kupffer cells release chemoattractant in response to oxygen radicals reducible by xanthine oxidase inhibition.

Topics: Animals; Chemokines, CXC; Chemotactic Factors; Enzyme Inhibitors; Growth Substances; Heparin; Intercellular Signaling Peptides and Proteins; Ischemia; Kupffer Cells; Liver; Liver Circulation; Male; Neutrophils; Peroxidase; Rats; Rats, Wistar; Reperfusion Injury; RNA, Messenger; Triazines; Xanthine Oxidase