The morphological changes of exocrine pancreas in chronic pancreatitis

The following changes were found by either light or electron microscopic ob servation of the pancreas in spontaneously developed chronic pancreatitis m odels (WBN/Kob rats, spontaneously hypertensive rats, and rats with common bile-pancreatic duct stones) and in experimental models of chronic pancreat itis (alcoholic pancreatitis, ischemic pancreatitis, and obstructive pancre atitis): 1) the units of lobules, which were constituted by acinar cell del etion, ductular proliferation, and fibrosis; and 2) tortuous or helical duc tal channels of pancreatic ducts with periductal fibrosis, which had many c rater-like depressions and very long cilia in their inner surface. These ar e considered to be the results of obstructive pancreatitis, which are cause d by the reactions of defensive factors against the increase of pancreatic duct pressure, including the apoptosis of acinar cells, the hyperplasia and hypertrophy of duct cells, a tighter junctional complex of duct cells, and periductal fibrosis.