Studies on early changes of exocrine pancreatic function in experimental pancreatitis
Since Classen's description there were numerous studies aboout acute pancreatitis but the pathogenesis is still remained obscure. For over a centry it has been known that human pancreatitis is often associated with biliary tract diseases and
The Opie's common channel theory is the oldest and most important contribution to an understanding of the etiology of acute pancreatitis whitch was initially derived from attempts by Claude Bernard. This theory proposes that pancreatic juice, passing via acommon channel into the common bile duct, is activated in the bile and the bile -enzyme mixture may then infilterate the pancreatic duct at low pressure causing hemorrhagic pancreatitis. Associated with this theory, reflux of duodenal contents, or activation of elastase or phospholipase is suggested as possible pathogenesis.
Alcohol has been proposed as a causative factor in chronic relapsing pancreatitis by its direct toxicity and indirectly mediated by releasing the gastrointestinal hormrnes.
At the present time it is difficult to single out one etiologic factor as the most important cause of pancreatitis. But the fundamental mechanism is thought to be autodigestion of the gland by its activated enzymes and pancreatic hypersecretion against obstruction to the outflow tract.
Many authors have claimed that duct obstruction is the basic etiological factor in pancreatitis. However the occlusion of main pancreatic duct alone does not cause hemorrhagic pancreatitis except mild edema and acinar atrophy. Present study
was undertaken to observe the early changes of exocrine pancreatic function by transient ductal obstruction and the pancreatic lesions induced with or without intraductal instillation of saline, alcohol or bile salt.
Fifty two albino rabbits of both sexes weighing 2.0kg around were divided into two experimental groups.
Experiment Ⅰ : Pancreatic juice was collected with pancreozymin stimulation before and after 3, 4 or 5 hour-obstruction of the pancreatic duct. At same tie blood sampling was done for the serum enzyme analysis.
Experiment Ⅱ : The pancreatic duct was temporarily obstructed by ligation for five hours with or without instillation of 2ml of saline (0.9%), ethyl alcohol (20v/v%) or chenodeoxycholic acid (1%). The blood sampling was done before obstruction and after release at various time interval until 91 hours.
Activity of amylase and lipase were determined by method of Nelson, and Cherry and Crandall method, respectively. Protein contents were measured by biuret reaction and pancreatic enzyme fractionation was carried out by isoelectric focusing using Ampholine carrier ampholyte, pH 3-10. The histopathologic changes
were observed by light microscope after hematoxylineosin stain.
The result obtained are summarized as follows:
1. The serum amylase and lipase were elevated more than 3 folds by transient obstruction of pancreatic duct, and enzymes and protein contents in the pancreozymin-stimulated pancreatic juice are significantly decreased to one fifth by 5 hour-obstruction.
2. The isoelectric focusing pattern of pancreozymin-stimulated pancreatic juice using pH 3-10 Ampholine carrier ampholyte showed 41 protein fractions and there procarboxypeptidase A isozyme bands. After 5 hour-obstruction of the pancreatic duct the protein staining degree and number of fractions were markedly decreased and moreover no procarboxypeptidase A band could be detected.
3. Five-hour ductal ligation with or without instillation of saline into pancreatic duct showed significant elevation of serum amylase but rapidly decreased by releasing the obstruction.
However in alcohol or cholate instillated group, serum amylase showed sustained elevation until 19 hours after release of the obstruction.
4. Pancreatic lesions were negligible by simple ligation of pancreatic duct for 5 hours.
But in alcohol or cholate instillated group the morphologic changes are marked and progressed even though the obstruction was removed.
By these findings it can be concluded that the exocrine pancreatic secretory functions are rapidly deteriorated by transient obstruction of the pancreatic duct and the elevated serum enzyme levels are more sustained when thy alcohol or bile
salt was flushed into pancreas.