INTESTINAL MUCOSAL PERMEABILITY TO CR-51-ETHYLENEDIAMINETETRAACETIC ACID IS INCREASED AFTER BILATERAL LOWER-EXTREMITY ISCHEMIA-REPERFUSION IN THE RAT

Background. Despite successful revascularization of ischemic extremiti es, multiogran dysfunction syndrome develops in some patients. Mechani sms responsible for this are not known; however, the gastrointestinal tract has been implicated as a possible mediator. Our objective was to demonstrate increased intestinal mucosal permeability after bilateral hindlimb ischemia-reperfusion (I-R) in a rodent model. Methods. Sixte en male Wistar rats were randomized either to 4 hours of bilateral hin dlimb tourniquet ischemia and 24 hours of reperfusion (n = 8) or contr ol groups (n = 8). The animals received 10 mu Ci Cr-51-ethylenediamine tetraacetic acid (EDTA) by gavage, and excretion was measured in urine collected every 8 hours in 16 animals and every 4 hours in 8 animals. Arterial blood pressure was monitored continuously. Intravenous norma l saline solution (3 ml/hr) with fentanyl (2 mu g/100 gm/hr) was conti nuously administered. Immediately before death complete blood count an d levels of arterial lactate, creatinine, and urea were obtained. Mese nteric lymph nodes were harvested from the ileocecal region and cultur ed. Distal small bowel and proximal colon were preserved for histologi c analysis. An additional 11 rats, six experimental and five control, were evaluated for mesenteric lymph node cultures only. Results. Urina ry excretion of Cr-51-EDTA was significantly greater in the I-R group between 0 and 8 hours (p < 0.02) and 8 to 16 hours (p < 0.0002) of rep erfusion. This increase occurred as early as 4 to 8 hours of reperfusi on (p < 0.0001). Urine volume in the I-R group was significantly reduc ed during 0 to 4 hours of reperfusion (p < 0.002). Hemoglobin in and l actate level were significantly different in the I-R growth. Leukocyte and platelet counts, levels of creatinine and urea, and colony counts from mesenteric lymph nodes were similar in I-R and control groups. B linded histologic analysis of bowel segments did not reveal morphologi c differences. Conclusions. Bilateral hindlimb I-R produces remote int estinal mucosal injury shown by significantly increased permeability t o Cr-51-EDTA. Such increased mucosal permeability may be important in the development of multiorgan dysfunction syndrome in patients who sus tain lower extremity I-R injury.