DETERMINATION OF A SAFE VASCULAR CLAMPING METHOD FOR LIVER SURGERY - EVALUATION BY MEASURING ACTIVATION OF CALPAIN-MU

Objective: To determine the safest method of hepatic vascular clamping associated with the least ischemia-reperfusion injury of the liver du ring liver surgery. Setting: University laboratories. Subjects: Sixty- five adult male Wistar rats. Methods: The hilar area of the left later al and median lobes of rat liver was clamped for 10 minutes (group 1), 15 minutes (group 2), or 20 minutes (group 3) followed by 5 minutes o f reperfusion. The procedure was repeated for a total period of ischem ia of 60 minutes in each group. Control rats underwent laparotomy with out vascular clamping. In addition to histological examination, we det ermined calpain Fr activity, a marker of liver injury, by Western blot ting using specific antibodies against the intermediate (activated) an d proactivated forms of calpain mu. Measurements were performed at the end of ischemia and after 2 hours of reperfusion. We also determined the degradation of talin, an intracellular substrate of calpain mu, by Western blotting. Results: The level of adenosine triphosphate and en ergy charge at 2 hours after reperfusion did not change after ischemia -reperfusion irrespective of the duration of ischemic cycle. After 60 minutes of intermittent ischemia followed by 2 hours of reperfusion, c ell membrane bleb formation, calpain mu activation, and talin degradat ion were detected in groups 2 and 3 but not in group 1. Conclusion: Th e safest method of hepatic vascular clamping that produces a minimum o r no ischemia-reperfusion injury is 60 minutes of 6 cycles of 10-minut e vascular clamping interrupted by 5 minutes of reperfusion.