Effects of hyperbaric oxygen treatment an neutrophil activation and pulmonary sequestration in intestinal ischemia-reperfusion in rats

Treatment with hyperbaric oxygen (HBO) has shown promising results in some models of ischemia, the major effect being a reduction in the local ischemi c damage. The present study investigated the effects of HBO treatment on ne utrophil activation and leukosequestration during reperfusion following int estinal ischemia in a rat model. The superior mesenteric artery was clamped for 2 h and subsequently reperfused for 90min. One group of male Sprague-D awley rats (n = 9) was given HBO and another group (n = 9) served as contro ls. Prior to ischemia, leukocytes and erythrocytes were separated, radiolab elled with (111)ln and Cr-51, respectively, and reinfused. Leukocyte transi t factor, the ratio between the mean passage time of leukocytes and erythro cytes was used to quantitate leukosequestration and the fraction of circula ting, spontaneously nitroblue tetrazolium (NBT)-reducing neutrophils was us ed to measure the degree of neutrophil preactivation. HBO treatment reduced the level of leukocyte pooling significantly, especially in the lungs but also, to a minor degree, in the systemic vascular bed. The percentage of NB T-positive cells increased in all animals after reperfusion, but the increa se was significantly reduced by HBO treatment. In conclusion, HBO treatment reduces leukosequestration and neutrophil preactivation following intestin al ischemia-reperfusion.