Pretreatment with activated protein C or active human urinary thrombomodulin attenuates the production of cytokine-induced neutrophil chemoattractant following ischemia/reperfusion in rat liver.

We investigated the role of anticoagulant in the ischemia/reperfusion injury of the liver, using activated protein C (APC), active human urinary thrombomodulin (UTM), and factor Xa blocked at the active site (DEGR-Xa). Liver ischemia was induced in male Wistar rats by occlusion of the portal vein with a microvascular clip for 30 minutes. Each anticoagulant was injected intravenously 10 minutes before clamping the portal vein. Serum concentrations of cytokine-induced neutrophil chemoattractant (CINC) were determined by enzyme-linked immunosorbent assay. The serum levels of CINC increased significantly following reperfusion, reaching a peak in 6 hours, and then decreasing gradually to control levels by 24 hours. CINC levels in rats pretreated with APC (500 U/kg), UTM (3,000 TMU/kg), or DEGR-Xa (10 mg/kg) peaked 3 hours following reperfusion and decreased rapidly to baseline level within 6 and 12 hours, respectively. These peak values were significantly lower than those observed in untreated rats (P < .01). Expression of CINC transcripts in liver tissue of untreated rats was evaluated by Northern blot analysis and peaked 3 hours following reperfusion. Pretreatment with these anticoagulants significantly decreased the expression of CINC messenger RNA transcripts as compared with untreated animals. Myeloperoxidase activity and the number of neutrophils accumulated into the liver 24 hours following ischemia/reperfusion were also significantly decreased in animals pretreated with these anticoagulants. In addition, correlations between the peak values of liver enzymes and serum CINC levels were found to be significant (P < .001). The inactive derivative of factor Xa, a selective inhibitor of thrombin generation, inhibited ischemia/reperfusion-induced increases in the serum concentration and messenger RNA transcript quantities of CINC. The inactive factor Xa also reduced hepatic accumulation of neutrophils after ischemia/reperfusion. These results indicate that the release of CINC is likely related to the hepatic microcirculation disturbance induced by microthrombotic occlusion following ischemia/reperfusion.