HEPATIC ISCHEMIA REPERFUSION AFFECTS LEUKOCYTE ROLLING AND VELOCITY/

Mechanisms of injury in hepatic ischemia/reperfusion injury are poorly defined, Leukocytes are thought to be important in the final mechanis m of hepatic damage. We intend to show the time course of abnormal leu kocyte activity in the liver after ischemia/reperfusion (I/R) injury. Left lobar hepatic ischemia was induced for 20 min in anesthetized C57 B1-6 mice. Measurements were taken at control, reperfusion, and matchi ng sham times (no ischemia) of 2, 5, 12, and 24 h. Measurements were t aken using rhodamine and fluorescein enhanced intravital microscopy. P ost sinusoidal venules were evaluated for numbers of rolling leukocyte s, leukocyte saltation, and leukocyte velocity. Data are expressed as number of rolling leukocytes per 100 mu m venule length (2 min). Stati stical analysis was by ANOVA. The number of rolling leukocytes at 5, 1 2, and 24 h of reperfusion (p<0.001) was significantly higher than con trol and sham-operated animals. Leukocyte velocities were significantl y slower in the 12 h I/R group when compared to sham animals (p< 0.001 ). These data show that there are definable and quantifiable changes i n leukocyte kinetics in the liver after ischemia/reperfusion, These ch anges, which lasted for 24 h, are likely due to upregulation of variou s endothelial cell adhesion molecules. Delineation of these mechanisms may be important in disease states such as shock, sepsis, and hepatic transplantation.