Effects of stop-flow ischemia, regional chemotherapy, and reperfusion on healing of bowel anastomosis in the rat

Abdominal anoxic perfusion (TAP) and aortic stop-flow (ASF) (Aigner's technique) have recently been used for application of regional chemotherapy (RCT) in advanced abdominal cancer. We studied the effect of ASF and RCT on healing of small bowel anastomosis. Four groups of rats were studied: 1 - controls - underwent small bowel resection and anastomosis (SBRA); 2 - SBRA followed by clamping of the subdiaphragmatic aorta for 10 minutes; 3 - treated like group 2 with the addition of an intra-aortic injection of 5-FU (20 mg/kg); 4 - treated like group 3, with the addition of an IV injection of superoxide dismutase (SOD - 50 mg/kg) prior to aortic clamping. The rats were sacrificed seven, 14, and 42 days postoperatively. Anastomotic healing was evaluated by measuring anastomotic bursting pressure (ABP) and histological parameters. There was a significant increase in ABP (p < 0.05) in groups 3 and 4 compared with 1 and 2. No differences in ABF between groups 1 and 2 were observed. Highest ABP was observed in the SOD group (group 4). There was a highly significant increase in anastomotic re-epithelialization (AR) (p < 0.0005) in the SOD group. No additional histological differences were observed among the other groups. We conclude that ASF and intra-aortic 5-FU do not seem to effect anastomotic healing in the rat. The addition of SOD enhances AR.