EFFECT OF ISCHEMIA ON THE CANINE LARGE-BOWEL - A COMPARISON WITH THE SMALL-INTESTINE

Mucosal injury caused by ischemia and reperfusion has been well docume nted with the small intestine, but little is known about the colon, In the present study, the effect of warm and cold ischemia on the canine colon was studied and compared to that on the small intestine, After in situ flushing, the small intestine and the colon from six beagle do gs were removed and stored for 0.5, 1.5, and 3 hr at 37 degrees C (war m ischemia) or for 1, 6, 12, 24, 36, and 48 hr at 4 degrees C (cold is chemia). Electrophysiology, permeability, biochemistry, and histopatho logy of the specimens at each ischemic period and after reperfusion in the Ussing chamber were determined, Warm and cold ischemia induced du ration-dependent suppression of electrophysiology in both organs, but the colonic mucosa retained higher activity of absorptive enterocytes and cryptic cells than the small intestine. Only the colon showed incr eased permeability of FITC-conjugated Dextran from the mucosal surface to the submucosal layer after prolonged ischemia, Changes in adenine nucleotides and purine catabolites were not markedly different between the organs. Histopathologic abnormalities during ischemia and after r eperfusion were more serious with the small intestine than with the co lon, Compared to warm ischemia, hypothermia lessened or delayed these morphofunctional derangements in both organs, which became universally worsened after reperfusion. Colonic mucosa receives morphofunctional derangements from ischemia and reperfusion, but the severity of the da mage was much less severe in the colon than in the small intestine. (C ) 1996 Academic Press, Inc.