Role of hepatovasculature in warm ischaemia-reperfusion injury of rat liver

Liver haemodynamics were studied after warm (37 degrees C) ischaemia of isolated rat livers for periods of 30 s (Group 1), 30 min (Group 2), and 60 min (Group 3) using a constant pressure system with a recirculating blood-free perfusate. Portal flow recovered to basal values within 6 min in livers from Group 1, whereas it was significantly reduced in Group 2 during the initial 15 min and in Group 3 during the first 33 min of reperfusion. Thus, the recovery of liver flow was proportional to the duration of ischaemia. By using the same mode of liver perfusion, the effect of norepinephrine on portal resistance was also studied in normal livers. At the beginning of reperfusion, the values of portal resistance in ischaemic livers were comparable to the values of portal resistance mediated by norepinephrine at concentrations between 10(-7) and 10(-6) mol/l in normal livers. The results suggest that vasoconstriction of the hepatovasculature may be a contributing factor to the reperfusion injury of the liver following warm ischaemia.