Abstracts
1997 Digestive Disease Week

Regulation of gene expression during reversible acute biliary pancreatitis.

J Dunn, C Li, GE York, RL Kao, W Browder. Department of Surgery, James H. Quillen College of Medicine, Johnson City, Tennessee.

Acute pancreatitis has an obscure pathogenesis and no effective clinical therapy. An animal model of reversible acute biliary pancreatitis in the male Sprague-Dawley rat has been established in our lab (J. Surg. Res. 63:419, 1996) by temporary occlusion of the common bile duct. The animals were sacrificed at 0, 5, 15, and 30 min as well as 1, 2, 3, 4, 6, 8, 10, 12, and 24 hrs after the induction of pancreatitis. The pancreas from each animal was frozen immediately and used for nuclear protein and total RNA extractions. NF-kappa-B binding activity was determined by electrophoretic mobility shift assay. TNF-alpha, IL-6, and pancreatitis associated proteins (PAP I, PAP II) gene expressions were measured by reverse transcription (RT)-PCR. Serum amylase was significantly increased at 1 hr after the induction of pancreatitis and reached 4 and 7 times the control level between 2 to 8 and 10 to 24 hrs, respectively. Serum total bilirubin was increased 3-fold (2~8 hrs) and 8-fold (10~ 24 hrs) during acute pancreatitis. NF-kappa-B binding activity was significantly higher around 1 hr and persisted up to 24 hrs. Both TNF-alpha and IL-6 mRNA levels were significantly increased within 15 min and peaked at 30 min. After a transient decrease of IL-6 mRNA it plateaued again at 4 hrs while the TNF-alpha mRNA remained elevated. The synthesis of PAP is induced during acute pancreatitis and PAP expression increased as a function of the severity of the disease. Pancreatic PAP I and II mRNA were dramatically increased at 8 hrs after bile duct occlusion. Inhibition of the electron entry from complex I to ubiquinone by the complex I inhibitor (amobarbital) or prevention of reactive oxygen intermediates accumulation by free radical scavenger (N-Acetyl-L-cysteine) significantly ameliorated the severity of pancreatitis. The induced NF-kappa-B activation and over-expression of TNF-alpha, IL-6, PAP I, and PAP II were also prevented by amobarbital or acetylcysteine. The data suggest that pathogenesis of acute biliary pancreatitis is mediated through reactive oxygen intermediates. The activation of NF-kappa-B and the over-expression of inflammatory cytokines are possible mechanisms of acute pancreatitis.