Ischemic preconditioning of small bowel mitigates the late phase of reperfusion injury: heme oxygenase mediates cytoprotection.

Background: Ischemia and reperfusion (IR) injury of the intestine is a major cause of morbidity and mortality following small bowel transplantation. The current study evaluates the effect of ischemic preconditioning (IPC) on the intestinal microcirculation in the late phase of IR injury of the intestine.

Methods: Sixty rats were randomly allocated to 5 study groups (n = 12 per group): (1) sham, (2) IR (3) IPC, (4) pyrrolidine dithiocarbamate (PDTC) (HO-1 inducer), and (5) zinc protoporhyrin (ZnPP) (HO-1 inhibitor). Mucosal perfusion and leukocyte-endothelial interactions were measured with the aid of an intravital microscope. At the end of the experiments, blood samples for lactate dehydrogenase (LDH) levels and biopsies of ileum for histologic evaluation were obtained.

Results: IPC significantly improved the mucosal perfusion and decreased the leukocyte-endothelial interactions. Histologic examination showed that ileal mucosa was significantly less injured in the IPC and PDTC groups as compared with the IR group.

Conclusions: IPC protects the intestine from late reperfusion injury. HO-1 is involved in this protection. These findings may be of significant importance in clinical small bowel transplantation.