A NEW ANIMAL-MODEL OF REVERSIBLE ACUTE-PANCREATITIS

Numerous animal models of acute pancreatitis are utilized to assess pa thophysiologic events and to evaluate therapeutic options. However, no ne of the small animal models simulates reversible biliary pancreatiti s with long-term follow-up (weeks). The present study was designed to create a reversible model of acute biliary pancreatitis in small exper imental animals. Male Sprague-Dawley rats were subjected to laparotomy , and the common bile duct was dissected free at its junction to the d uodenum. Experimental animals had a polypropylene tie occluder passed around the common bile duct and brought out through a separate stab wo und in the abdominal wall. The duct was occluded for 24 hr; the blocka ge was then relieved and the tie withdrawn from the animal. Sham-opera tive animals had similar surgical procedures but without the occluder. Serum amylase values on Days 1 and 2 following surgery were significa ntly increased in the experimental group, but were not different hom t hose of control animals on Day 3 or 4, suggesting reversibility of thi s biliary pancreatitis model, Likewise, serum bilirubin levels were in creased in the experimental group on Days 1 and 2. Histologic analysis revealed edema, zymogen degranulation, inflammatory infiltration, vac uolization of acinar cells, and focal areas of fat and parenchymal nec rosis in the experimental group. Only mild edema was observed in the s ham operative controls due to surgical manipulation. Pancreatic tissue s obtained at 1 week postinduction of pancreatitis showed near total d estruction of the architecture and dissolution of zymogen granules; in contrast, histology at the 3rd week showed almost normal-appearing pa ncreas with return of zymogen granules, suggesting recovery from the a cute pancreatitis. This reproducible and reversible model of acute pan creatitis in the rat will provide for further studies in the pathogene sis of pancreatitis and its therapeutic interventions. (C) 1996 Academ ic Press, Inc.