On PACAP-aggravated experimental acute pancreatitis / 生物医学工程学杂志

ABSTRACT

The role of PACAP (pituitary adenylate cyclase activating polypeptide), a peptidergic transmitter, in the pathogenesis of acute pancreatitis is not yet clear. This experiment was conducted to examine the action of exogenous PACAP on rat pancreas and on the course of experimental acute pancreatitis. The results showed that 5-30 microg/kg of PACAP slightly raised the serum amylase level, induced pancreatic edema (23.88% +/- 2.532%-25.86% +/- 1.974% of experiment groups versus 29.21% +/- 5.657% of control group), inflammatory cell infiltration, vacuolization of acinar cells, and occasionally fatty and parenchymal necroses. 15-30 microg/kg of PACAP aggravated cerulein-induced acute pancreatitis; the pancreatic edema became more marked (13.45% +/- 2.045%-17.66% +/- 4.652% of expreiment groups versus 21.83% +/- 3.013% of cerulein group, P<0.05), the serum amylase level became higher; and ascites, pancreatic bleeding, fatty and parenchymal necroses, and extensive vacuolization of acinar cells appeared. For sodium taurocholate-induced pancreatitis, 5-10 microg/kg of PACAP mildly attenuated the pancreatic edema, reduced the serum amylase level (1986.91 +/- 710.97-2944.33 +/- 1182.47 IU/L vs 3690.87 +/- 2277.99 IU/L, P<0.05), whereas it caused multifocal hemorrhage and prominent necrosis in pancreas. Except the cerulein-induced pancreatitis groups, other groups were found to have reduced pancreatic functional capillary density (FCD); when pancreatic edema was taken into consideration and calibrated FCD was introduced (FCD weighted against pancreatic wet/dry ratio), all groups revealed increases in pancreatic functional capillaries when compared with normal control. In conclusion, PACAP is proinflammatory in the pathogenesis of acute pancreatitis, PACAP plus cerulein can induce acute hemorrhagic/necrotizing pancreatitis, and the action of PACAP on cerulein-induced panceatitis may differ from that on sodium taurocholate-induced one. In this experiment, pancreatic FCD was underestimated due to pancreatic edema.