INTERLEUKIN 1 RECEPTOR BLOCKADE REDUCES TUMOR NECROSIS FACTOR PRODUCTION, TISSUE INJURY, AND MORTALITY AFTER HEPATIC ISCHEMIA-REPERFUSION IN THE RAT1

The inflammatory cytokines interleukin (IL) 1 and tumor necrosis factor (TNF) may play an important role in hepatic ischemia-reperfusion (I/R) injury. To study the role of IL-1 in hepatic I-R injury, we investigated the effect of pretreatment with IL-1 receptor antagonist (IL-1ra) on the production of IL-1, TNF, histological findings in the liver, and the survival rate for 7 days. Rats were subjected to 90 min of partial liver warm ischemia by clamping the vessels of the left and middle lobes. In the IL-1ra-treated group, IL-1ra was given 5 min before liver ischemia was induced. IL-1alpha and TNF levels were determined in blood and liver at 0, 30, 90, and 180 min after reperfusion. In a second experiment to determine the effect of IL-1ra pretreatment on survival rate, after 90 min of partial liver ischemia, the right lateral and caudate lobes were excised, leaving only the ischemic lobes. In both groups, IL-1alpha was undetectable in blood, but increased in liver tissue. TNF increased in both blood and liver tissue as reperfusion time increased. Histological evidence of tissue injury was minimal in the IL-1ra-treated group. Furthermore, in the IL-1ra-treated group, the production of TNF decreased in both blood and liver tissue compared with the nontreated group. Survival rates in the IL-1ra-treated and nontreated group were 80% and 30%, respectively. The data demonstrated that the production of IL-1 and TNF increases in hepatic I-R injury and that pretreatment with IL-1ra protects the liver from ischemic insult, indicating an important role for IL-1 in I-R injury.