Hypoxic preconditioning ameliorates intestinal epithelial barrier defect and bacterial translocation in ischemia/reperfusion injury

Abstract

Intestinal epithelium and mucosal immune cells are defensive barriers against enteric microbial influx. Intestinal ischemia / reperfusion (I/R) induced mucosal injuries associated with bacterial translocation. Hypoxic preconditioning (HPC) protects heart and brain against ischemic insults. The aim of this study was to assess the effect of HPC in preventing intestinal I/R‐induced barrier defects. Male Wistar rats were raised either in normoxic air or in a hypobaric chamber (380 mmHg) for 21 days (17 hrs/day) for HPC. I/R rats received 20 min occlusion of superior mesenteric artery and 1 hour of reperfusion. Sham‐operated rats served as controls. In normoxic rats, I/R induced destruction of ileal mucosa, e.g. villi shortening and epithelial detachment, as well as increase of the bacterial colony forming units (CFU) in the liver and spleen. Rats exposed to HPC prior to I/R showed a reduction of mucosal damages and lowered CFU in internal organs. Moreover, elevated levels of myeloperoxidase activity and cytokine‐induced neutrophil chemoattractant‐1 were found in ileum of HPC I/R rats compared to those of normoxic I/R rats. In conclusion, HPC ameliorated I/R‐induced intestinal barrier defect and bacterial translocation. This protective mechanism may be partly attributed to enhanced neutrophil activation in the intestinal mucosa.