A novel inhibitor of Rho-associated protein kinase, Y-27632, ameliorates hepatic ischemia and reperfusion injury in rats.

BACKGROUND A Rho-ROCK signal system induces vascular contraction and neutrophil migration, both of which are characteristic features found with ischemia and reperfusion injury of the liver. We tested our hypothesis that a novel ROCK I inhibitor, Y-27632, attenuates hepatic ischemia and reperfusion injury. METHODS Rats underwent 70% partial hepatic ischemia for 120 minutes and subsequent reperfusion. Y-27632 of 10mg/kg was given orally 1 hour before ischemia, while distilled water was given to the control animals. One week animal survival, systemic hemodynamics, hepatic tissue blood flow, liver function tests, plasma endothelin-1, serum hyaluronic acid levels, myeloperoxidase activity and malondialdehyde level in liver tissue, membrane attack complex-1 and intracellular adhesion molecule-1 staining, and histological architecture were analyzed. RESULTS Y-27632 prolonged 1-week animal survival from 25% of untreated animals to 75% accompanied with significant amelioration of hepatic tissue blood flow, liver function tests and histological architecture without any adverse effects on systemic hemodynamics. In addition, plasma endothelin-1 and serum hyaluronic acid levels decreased markedly compared to the control, concomitant with remarkable suppression of membrane attack complex-1 stain positive neutrophils infiltration, myeloperoxidase activity and malondialdehyde level. CONCLUSION Present study suggests that activation of a Rho-ROCK signal system is associated with ischemia and reperfusion injury of the liver, and that Y-27632 may be an attractive agent for application in major liver resection using temporary inflow occlusion and hepatic preservation.