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ge was then relieved and the tie withdrawn from the animal.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.