[Effects of chronic and progressive obstruction of the main pancreatic duct on the epithelium of the ducts and the exocrine pancreatic tissue].

The alarming increase in the number of clinical cases of carcinoma of the pancreas provides the stimulation to search for an experimental model that produces chronic progressive obstruction of the main pancreatic duct. Fifteen mongrel dogs were studied for 1 to 11 weeks. To induce chronic progressive obstruction of the pancreatic duct, a cellophane tape was placed around the main duct adjacent to its entrance into the duodenum and tied over a needle with a diameter identical to that of the duct; the needle was then withdrawn. All minor ducts were identified by pancreatography and then ligated with 2-0 silk. Each animal was followed up by repeated ductal pancreatography and measurements of serum amylase and alkaline phosphatase concentrations. Histologic, histochemical and ultrastructural studies were also performed. On both gross and microscopic examination each animal demonstrated chronic pancreatitis with preservation of the islands of Langerhans. In the early period (4 to 7 days) complete ductal obstruction occurred as demonstrated by pancreatography and by elevated serum values for amylase (264% increase) and alkaline phosphatase (209% increase). In contrast to what is seen after acute ductal ligation, the ductal epithelial cells increased in number and height. At 4 weeks a new collateral ductal system had developed and serum amylase and alkaline phosphatase values had reverted to normal. This model is useful in studying the kinetics of pancreatic ductal regeneration and the pathophysiology associated with chronic pancreatic ductal obstruction.