Hirulog effect in rat endotoxin shock

Hirulog(TM) is a thrombin catalytic site inhibitor which exhibits specificity for the anionic binding exosite of alpha thrombin. Here, we have evaluated the effect of Hirulog(TM) (1, 5 and 10 mg/kg, 30 min pretreatment) in a rat model of endotoxemia. Intravenous injection of lipopolysaccharide from E. coli (25 mg/kg) serotype 0127:B8) caused decreases in blood pressure which were significantly reduced (about 60%) in animals pretreated with Hirulog(TM). Rat survival to endotoxin was significantly increased in Hirulog(TM) pretreated group (5 and 10 mg/kg) up to 24 hours. Hirulog(TM) at the dose of 10 mg/kg inhibited both endotoxin-induced leukopenia at 30 and 60 minute points and thrombocytopenia at 30 minute point but not at 90 and 120 minute points. Fibrinogen levels were significantly reduced after 2 hours following endotoxin administration. Pretreatment with Hirulog(TM) (5-10 mg/kg i.v.) 30 min prior to administration of endotoxin prevented changes in fibrinogen plasma levels. These results demonstrate that Hirulog(TM)-induced inhibition of thrombin is effective in reducing toxic and lethal effects of endotoxin.