Alterations in intestinal permeability and blood flow in a new model of mesenteric ischemia

Disturbances in intestinal circulation for even short periods of time can produce mucosal injury, translocation of gut bacteria, and multiple organ failure. We recently reported a model of intestinal ischemia that included occlusion of the superior mesenteric artery (SMA) and interruption of collateral arcades from the right colic and jejunal arteries for 20 min. This present study was designed to characterize further our model of intestinal ischemia by quantitatively assessing changes in intestinal permeability (plasma to luminal clearance of 51Cr-labeled EDTA) and intestinal blood flow (IBF) (microspheres). A total of 89 rats were included for study; mean arterial blood pressure and acid-base balance were not significantly altered by intestinal ischemia or reperfusion. Baseline measurements of 51Cr-labeled EDTA were not significantly different among the experimental animals, and clearance did not change throughout the experimental period in the sham-ischemic group (N = 14). Clearance of 51Cr-labeled EDTA at the end of 20 min of intestinal ischemia (0.194 +/- 0.057 ml/min/100 gm, N = 17) was significantly greater than that measured at control (0.079 +/- 0.006 ml/min/100 gm, P less than 0.05). In addition, clearance measurements during reperfusion (20 min, 0.362 +/- 0.051; 60 min, 0.267 +/- 0.084 ml/min/gm) were significantly higher than those measured at the end of ischemia. Baseline IBF was similar in all rats (N = 42); SMA occlusion reduced IBF by 99% from baseline (from 1.4 +/- 0.27 to 0.014 +/- 0.001 ml/min/gm, N = 20). Removal of the SMA clip returned intestinal perfusion to baseline values (1.72 +/- 0.51 ml/min/g).(ABSTRACT TRUNCATED AT 250 WORDS)