No protective function found in Wistar rats submitted to long ischemia time and reperfusion after intermittent clamping of the total hepatic pedicle.

BACKGROUND: Although the intermittent Pringle maneuver is used for major transplant surgery, traumas, and hepatic protection, long ischemia time and reperfusion may limit some protection in Wistar rats. The aim of the study was to evaluate the protection effects of intermittent clamping in the total hepatic pedicle after a long period of ischemia and reperfusion in Wistar rats. METHODS: Forty-two male Wistar rats, weighing ± 327.7 g, were anesthetized intravenously with sodium thiopental and given a U-shaped incision in the abdomen. The total hepatic pedicle was isolated and subjected to clamping with a microvascular clamp. Groups included were the continuous group (CG, n = 14, 40 minutes of ischemia/40 minutes of reperfusion); the intermittent group (IG, n = 14, 4 cycles a 10 minute ischemia/reperfusion 10 minutes); and the sham group (SG, n = 14, 80 minutes of observation time). Blood collection for transaminase dosage was carried out, and hepatic biopsy specimens were taken for mitochondrial respiration and histological evaluation. RESULTS: In groups CG and IG, aspartate aminotransferase and alanine aminotransferase enzymes were elevated in comparison to group SG (P < .008); mitochondrias, when stimulated by use of adenosine diphosphate or carbonylcyanide p-trifluoromethoxyphenylhydrazone, had a significant decrease in mitochondrial respiration (P < .05), and the respiratory control ratio in the ischemic groups was lower (P < .03) when compared with the GS. On histological examination, 100% of the GC had lesions: 33% focal hemorrhagic necrosis, 17% sinuzoidal congestion and/or vacuolization, and 50% venous congestion; in the IG, 100% had lesions: 43% sinusoidal congestion and/or vacuolization and 57% venous congestion. CONCLUSIONS: The intermittent total hepatic pedicle clamping for a long period of time in the Wistar rats had no efficacy in protection of liver injury.

Late biliary obstruction in Wistar rats after intermittent hepatic pedicle clamping.

INTRODUCTION: The temporary vascular occlusion of hepatic flow is one of the essential procedures in hepatic surgery. AIM: Evaluate the late liver alterations after intermittent pedicle hepatic clamping (IHPC) in Wistar rats. METHODS: Male Wistar rats (n = 14) with average weight of 281.1 g, were anesthetized with intraperitoneal ketamine 5%. The IHPC group (n = 7) was submitted to U-shaped abdominal incision; the hepatic pedicle was isolated and submitted to IHPC ischemia 4 times, 5 minutes each, followed by reperfusion 4 times, 5 minutes each. The simulated operation group (n = 7) was subjected to anesthesia, laparotomy, and manipulation of the hepatic pedicle. On day 35, after fasting for 12 hours, liver biopsies were collected and blood was tested for liver aminotransferases (aspartate aminotransferase/alanine aminotransferase). RESULTS: All the IHPC group animals had a dilated common bile duct and increased liver enzymes (P < .05 by Mann-Whitney test). Ductular proliferation (100% of cases), porta-porta septa (42.8%), formation of lumps (42.8%), foci of necrosis (14.2%), and bile plugs (14, 2%) were observed only in the IHPC group. CONCLUSION: In rats, IHPC caused morphologic features leading to biliary obstruction.