Pathophysiological appraisal of an extracorporeal portosystemic shunt in total hepatic ischemia model in rats

Abstract

Introduction: Animal models of total hepatic ischemia are restricted by concomitant splanchnic congestion from portal triad occlusion. This study was performed to clarify a pathophysiological advantages of an extracorporeal portosystemic shunt (PSS) in total hepatic ischemia model in rats. Methods- Using a polyethylene tube with 0.86 or 1 mm inner diameter, PSS was produced between the mesenteric vein and the jugular vein. A total hepatic ischemia model with PSS was compared with a partial ischemic model with hepatectomy of non-ischemic lobes as well as a total ischemic model without PSS. The well-tolerated ischemic period for the liver, portal pressure at 10 minutes after hepatic ischemia, portal endotoxin levels at 1 hour after reperfusion, and histological evaluation of the small bowel just before reperfusion and oxygen saturation index (ISO2) of the small intestinal blood through the experiment were assessed among the models. Results: Animals without PSS poorly tolerated 30 minutes of total hepatic ischemia with 88% mortality during 24 hours after reperfusion. Animals subjected to total hepatic ischemia with PSS or partial hepatic ischemia could tolerate a longer period of ischemia (60 minutes) with significantly higher ISO2 of the small intestine and lower portal pressure during ischemia, portal endotoxin levels 1 hour after reperfusion (p < 0.01), and less histological damage of the small bowel, when compared to those of the non-shunted total ischemia group. The groups of total hepatic ischemia with a shunt tube of 1 mm inner diameter and partial hepatic ischemia significantly prevented the elevation of portal endotoxin level, unlike that with a shunt tube of 0.86 mm inner diameter. Conclusions: Model of total hepatic ischemia with PSS of 1 mm inner diameter was strikingly similar to that of partial hepatic ischemia in pathophysiology during hepatic ischemia. Application of PSS tube of 1 mm or more inner diameter offers a pathophysiological advantage in the experiments of total hepatic ischemia and reperfusion.