Serosal injury in the equine jejunum and ascending colon after ischemia-reperfusion or intraluminal distention and decompression

Objective-To document morphologic changes that occur in equine intestinal s erosa after experimentally induced ischemia and subsequent reperfusion (jej unum, ascending colon) or after intraluminal distention and decompression ( jejunum). Study Design-Morphologic effects of ischemia-reperfusion or intraluminal di stention-decompression determined on the serosal layer of the equine jejunu m. The large colon serosa was evaluated after ischemia-reperfusion injury. Animals or Sample Population-Seven adult horses. Methods-After induction of general anesthesia and ventral median celiotomy, ischemia was created by arteriovenous (AVO) and lumen occlusion of a 20-cm segment of jejunum and ascending colon for 70 minutes, followed by a 60-mi nute reperfusion period. Intraluminal distention (25 cm H2O) was created in a second 20-cm jejunal segment and maintained within the abdomen for 120 m inutes, followed by a 120-minute decompression period. Seromuscular biopsie s were obtained upon entering the abdomen and after the ischemic and reperf usion periods, and after the distention and decompression periods along wit h corresponding control seromuscular biopsies. Samples were processed and e xamined by light microscopy, transmission electron, and scanning electron m icros copy. Results-Ischemia and reperfusion, and intraluminal distention and decompres sion, resulted in severe morphologic changes in the seromuscular layer of e quine jejunum. A similar period of ischemia-reperfusion caused minimal chan ges in the ascending colon serosa. Conclusion-Adult equine jejunum sustains more serosal damage than the ascen ding colon after similar periods of ischemia-reperfusion injury. Intralumin al distention and subsequent decompression causes serosal damage in the equ ine jejunum. Clinical Relevance-The small intestine is more susceptible to seromuscular layer damage than the ascending colon. (C) Copyright 2001 by The American C ollege of Veterinary Surgeons.