Examination of Protective Effect of Ischemic Postconditioning After Small Bowel Autotransplantation

Abstract

Ischemia/reperfusion (I/R) injury is a serious condition that results from some surgical procedures, including intestinal transplantation. Ischemic postconditioning is defined as brief periods of reperfusion alternating with reocclusion applied during the early minutes after reperfusion. The objective of this study was to investigate the effect of ischemic postconditioning before small bowel autotransplantation. Total orthotopic intestinal autotransplantation was performed in 30 white domestic pigs. Grafts were stored in cold University of Wisconsin solution for 1, 3, or 6 hours. Duration of reperfusion was 3 hours in all grafts. Before reperfusion, the intestine was postconditioned via 3 cycles of ischemia for 30 seconds and reperfusion for 30 seconds (ischemic postconditioning protocol). Tissue from the small intestine was obtained after laparotomy (control group) and at the end of reperfusion periods. To monitor oxidative stress, tissue concentrations of malondialdehyde and reduced glutathione, and activity of superoxide dismutase were determined at spectrophotometry. Tissue damage on sections stained with hematoxylin- eosin was evaluated using a quantitative method (Scion Image software; Scion Corp, Frederick, Maryland). Our results demonstrated that ischemic postconditioning significantly decreased the reperfusion-ended lipid peroxidation value (mean ± SEM, 142.0 ± 7.1 μmol/g vs 125.0 ± 2.1 μmol/g; P < .05). Moreover, the capacity and activity of endogenous antioxidant protective systems (glutathione 789 ± 8.0 μmol/g vs 934 ± 5.7 μmol/g, and superoxide dismutase 110 ± 9 IU/g vs 126 ± 4 IU/g; P < .05) remained higher in the ischemic postconditioning groups compared with tissues without ischemic postconditioning. At quantitative analysis, tissue injury was increased by the duration of cold preservation. The greatest injury was observed in the mucosal and submucosal layers and in the depth of crypts after 6 hours of preservation. Ischemic postconditioning significantly decreased intestinal wall injury in each group ( P < .05). It was concluded that ischemic postconditioning before reperfusion mitigated oxidative stress and histologic damage during small bowel autotransplantation.