A superoxide dismutase mimetic with catalase activity (EUK-8) reduces the organ injury in endotoxic shock

Reactive oxygen species contribute to the multiple organ failure in endotoxic shock. Here, we investigate the effects of a salen-manganese complex, which exhibits both superoxide dismutase and catalase activity (EUK-8), on the circulatory failure, renal and liver injury and dysfunction caused by endotoxin in the anaesthetised rat. Endotoxaemia (6 mg/kg i.v., Escherichia coli lipopolysaccharide) for 6 h caused hypotension, renal dysfunction and liver injury. Treatment of rats with EUK-8 (0.3 or 1 mg/kg bolus injection followed by an infusion of 0.3 or 1 mg/kg/h) attenuated the renal and liver injury and dysfunction in a dose-related fashion. In addition, the higher dose of EUK-8 attenuated the delayed hypotension caused by endotoxin in the rat. Thus, an enhanced formation of reactive oxygen species importantly contributes to the circulatory failure, as well as the organ injury and dysfunction associated with endotoxic shock. We propose that small molecules, which have the catalytic activity of both superoxide dismutase and catalase, may represent a novel therapeutic approach for the therapy of endotoxic shock.