Background: Angiotensin II has been implicated in the pathogenesis of vascular inflammation in various organs. The aim of the present study was to examine the effect of angiotensin II type I receptor antagonist, CV-11974, on reperfusion-induced small intestinal injury in rats.
Methods: Intestinal damage was induced by clamping both the superior mesenteric artery and the celiac trunk for 30 min followed by reperfusion for 60 min in male Wistar rats. CV-11974 was given to the rats by intravenous injection 1 h before the vascular clamping. The intestinal mucosal injury and inflammation were evaluated by biochemical markers and histological findings. Thiobarbituric acid reactive substances and tissue-associated myeloperoxidase (MPO) activity were measured in the gastric mucosa as indices of lipid peroxidation and neutrophil infiltration. The expressions of pro-inflammatory cytokines (CINC-1) in intestinal mucosa were measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-PCR (RT-PCR). In additional experiments with an in vitro flow system, human neutrophils were perfused on human umbilical vein endothelial cells (HUVEC) pretreated with anoxia-reoxygenation with or without CV-11974 and then the adhesive neutrophils were counted.
Results: Reperfusion after ischemia resulted in an increase in luminal protein concentrations, hemoglobin concentrations, thiobarbituric acid reactive substances, and MPO activity. Pretreatment with CV-11974 significantly inhibited the increases in these parameters. CV-11974 also inhibited increases in intestinal CINC-1 protein and mRNA expression induced by ischemia-reperfusion. Moreover, in an in vitro study, CV-11974 significantly inhibited the adherence of neutrophils to HUVEC exposed to reoxygenation after anoxia.
Conclusions: These results suggest that the blockade of angiotensin II type I receptor by treatment with CV-11974 remarkably reduced the reperfusion-induced intestinal injury.