Background
Intestinal ischemia/reperfusion (IR) is associated with disruption of gut barrier function and concomitant bacterial translocation into the circulatory system, thus enhancing septic complications. Postconditioning may be a suitable method for reducing intestinal IR injury. We aimed to characterize the effects of postconditioning on changes of intestinal tight junction protein expression, bacterial translocation rates and inflammatory responses caused by intestinal IR injury.

Materials and Methods
12 hours prior operation male Wistar rat were gavaged with 1mL 1010CFU/mL GFP-expresser E.coli suspension and were randomized into three groups (n=15), sham operated, IR- and PC- groups. Animals underwent 60 minutes of superior mesenteric artery occlusion, followed by 6 hours of reperfusion. Postconditioning was performed at the onset of reperfusion by 6 alternating cycles of 10/10 seconds reperfusion/reocclusion. Blood and tissue samples were taken at the end of reperfusion, for histological, bacteriological and serum analysis.

Results
Postconditioning significantly ameliorated mucosal free radical stress compared with the IR- group. The PC-group presented a more favorable claudin-2,-3 and zonula occludens-1 expression pattern compared with the IR-group. The rates of bacterial translocation to distant organs significantly decreased with the use of postconditioning. The histopatological lesions of the jejunum and ileum and the serum-IL6,-TNFx levels were significantly higher in the IR-group compared with the PC-group.

Conclusion
The use of postconditioning at the onset of reperfusion was able to improve the intestinal mucosal barrier integrity upon mesenteric IR, and thus reduced the incidence of bacterial translocation and the development of a systemic inflammatory response.