A Novel Model of Severe Gallstone Pancreatitis: Murine Pancreatic Duct Ligation Results in Systemic Inflammation and Substantial Mortality

Abstract

Background: Suitable experimental models of gallstone pancreatitis with systemic inflammation and mortality are limited. We developed a novel murine model of duct-ligation-induced acute pancreatitis associated with multiorgan dysfunction and severe mortality. Methods: Laparotomy was done on C57/BL6 mice followed by pancreatic duct (PD) ligation, bile duct (BD) ligation without PD ligation, or sham operation. Results: Only mice with PD ligation developed acute pancreatitis and had 100% mortality. Pulmonary compliance was significantly reduced after PD ligation but not BD ligation. Bronchoalveolar lavage fluid neutrophil count and interleukin-1β concentration, and the plasma creatinine level, were significantly elevated with PD ligation but not BD ligation. Pancreatic nuclear factor ĸB (p65) and activator protein 1 (c-Jun) were activated within 1 h of PD ligation. Conclusion: PD-ligation-induced acute pancreatitis in mice is associated with systemic inflammation, acute lung injury, multiorgan dysfunction and death. The development of this novel model is an exciting and notable advance in the field.

Systemic Inflammation with Multiorgan Dysfunction Is the Cause of Death in Murine Ligation-Induced Acute Pancreatitis

“…Midline laparotomy was performed on mice under general anesthesia with isoflurane. 1 Postoperatively, mice were allowed access to food and water ad libitum and were given buprenorphine analgesia and 1 cm 3 sterile normal saline s.c. hydration twice daily. The mice were monitored for physical activity, grooming, alertness, response to stimulation, and other signs of stress at least two times daily.…”

“…The mice were studied in three experimental groups: (1) sham operation (S): the distal bile-pancreatic duct was dissected but not ligated, (2) bile duct ligation (BD): only the common bile duct was ligated prior to its junction with the splenic portion of the pancreatic duct, and (3) distal common bile-pancreatic duct ligation (PD): the common bile-pancreatic duct was ligated near its junction with the duodenum. In our previous study, 1 we have already shown that acute pancreatitis induced by PD alone results in similar mortality and morphological pancreatic changes as PD+BD, and therefore we limited our studies to PD in the present study. It must be noted that PD will cause biliary obstruction in addition to obstructing outflow from the pancreatic ductal system and that BD alone for 2 weeks is not associated with mortality in our model.…”

“…It must be noted that PD will cause biliary obstruction in addition to obstructing outflow from the pancreatic ductal system and that BD alone for 2 weeks is not associated with mortality in our model. 1 Therefore, BD is a useful control group to compare and contrast the influence of biliary obstruction alone with biliary obstruction in relation to acute pancreatitis induced by PD. For time-course studies, sham-operated and BD controls were electively euthanized on days 2, 3, or 4, to serve as controls Fig.…”

“…Dr. Meyerholz (Director, Comparative Pathology Laboratory, University of Iowa) independently conducted the morphological and morphometric analyses, as described previously. 1,2 Bronchoalveolar Lavage Under general anesthesia, immediately prior to euthanasia, a tracheotomy tube was inserted and the lungs were filled with 1 ml of sterile saline that was then siphoned out and the process was repeated 3 times. The bronchoalveolar lavage (BAL) fluid was centrifuged at 290×g for 10 min at 4°C, and the cell pellet was re-suspended in phosphatebuffered saline.…”

“…1 As mortality following murine pancreatic duct ligation has not been described previously by other investigators prior to our original description, 1 we performed the present study to identify the possible factors that may contribute to the mortality associated with this model. Our strategy was to determine the time course of death in ligation-induced acute pancreatitis in mice and to correlate our findings with other important observations such as systemic cytokine release and distant organ injury.…”