Cytokine expression and induction of acinar cell apoptosis after pancreatic duct ligation in mice

To clarify the role of cytokines and acinar cell apoptosis in the pathogenesis of acute pancreatitis, we investigated the expression of intrapancreatic cytokines and apoptosis-related molecules in mice after pancratic duct ligation (PDL). From day 1 or 3 after PDL, the expression of interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-1 beta receptor antagonist, IL-6, IL-10, and tumor necrosis factor (TNF-alpha) mRNA were up-regulated in the pancreas, suggesting that these cytokines may be involved in the development of pancreatitis after PDL. Acinar cell apoptosis was observed in the pancreas at rates of 0.13 +/- 0.03, 1.32 +/- 0.38, and 0.86 +/- 0.23% on days 1, 3, and 7 after PDL, respectively. Significant increases in intrapancreatic mRNA levels of TNF-alpha, Fas ligand (FasL), and IL-1 beta-converting enzyme (ICE) were observed from day 3 after PDL with the appearance of acinar cell apoptosis, The serum amylase activity peaked on day 1 after PDL and gradually decreased on days 3 and 7 after PDL, These results suggest that acinar cell apoptosis induced after PDL may modulate the progression of acute pancreatitis by reducing the release of digestive enzymes and may therefore be a host defense mechanism, and that acinar cell apoptosis after PDL may be mediated by the TNF-alpha and/or Fas/FasL and ICE system.