Exogenous and Endogenous Nitric Oxide Donors Improve Post-Ischemic Tissue Oxygenation in Early Pancreatic Ischemia/Reperfusion Injury in the Rat

INTRODUCTION: In pancreatic ischemia/reperfusion (IR) injury (IRI) the role of nitric oxide (NO) is not completely understood. Using a rat model of normothermic in situ IRI, the effect of endogenous and exogenous NO donors on post-ischemic tissue oxygenation and tissue damage was investigated. METHODS: IR was induced by 2-hour normothermic in situ ischemia of a pancreatic tail segment pedunculated on the splenic vessels with 2 h of reperfusion in an untreated, an L-arginine- and a sodium-nitroprusside-treated group (Wistar rats, n = 7/group). Animals without ischemia served as controls. Tissue oxygenation (pO(2ti)) was monitored using a pO2-sensitive Clark-type electrode. Histological investigation was performed following a semiquantitative score (edema, vacuolization, PMN infiltration, necrosis). Plasma lipase was another marker of organ damage. RESULTS: The administration of L-arginine and sodium nitroprusside caused a significant amelioration of the decrease in pO2i) after reperfusion compared to IR animals (p < 0.05). Histological damage was also reduced in the NO donor groups (p < 0.05). After reperfusion, plasma lipase in the L-arginine-treated animals was significantly lower compared to IR and sodium nitroprusside (p < 0.05). CONCLUSIONS: The administration of both endogenous and exogenous NO donors is protective in IRI of the rat pancreas which can be seen by an improvement in post-ischemic tissue oxygenation which indicates better nutritive tissue perfusion, amelioration of the histological tissue injury and, in L-arginine animals, lower lipase levels. NO donors could be useful in the prevention and reduction of the pancreatic IRI.