Effects of intestinal ischemia-reperfusion injury on rat peripheral blood neutrophil activation

Peripheral blood neutrophil activation status is indicative of remote organ damage after intestinal ischemia secondary to aortic aneurysm repair. However, the effects of direct intestinal ischemia-reperfusion (I/R) injury on neutrophil activation and its reflection of remote organ injury have not been evaluated. DA rats were subjected to 30 min of intestinal ischemia or sham surgery. Blood samples were taken before ischemia and 30, 60, and 120 min after reperfusion. Neutrophil counts were quantified and CD11b, CD62L, and NKR-P1 expression was assessed using flow cytometry. The sham procedure induced increases in neutrophil numbers (P < 0.001), which was transiently attenuated in animals subjected to intestinal I/R injury. CD11b expression increased in both groups, whereas CD62L and NKR-P1 (P < 0.01) expression decreased in both groups. These findings suggest that even mild surgical procedures induce demargination of neutrophils. Monitoring the peripheral blood for activated neutrophils is of no value in assessing the severity of direct intestinal I/R injury or predicting remote organ damage after intestinal ischemia.