Proteases and protease inhibitors in cerulein-induced acute pancreatitis in rats

Background Proteases and protease inhibitors are important in acute pancreatitis (AP), although little is known about the time course in cerulein-induced AP in the rat. Materials and methods. AP was induced by supramaximal stimulation of cerulein, 10 mu g/kg/h, and during 72 h we measured lipase, amylase, albumin, prekallikrein, factor X, alpha(1)-protease inhibitor, alpha(1)-macroglobulin, alpha(2)-antiplasmin, antithrombin ill tall in plasma) and macroscopic and histologic variables. Results. Within 12 h an edematous pancreatitis was evident with peak values of peritoneal exudate, pancreatic wet weight ratio, and plasma amylase and lipase activities. Histologically, edema and vacuolization were prominent already after 3 and 6 h, respectively, while inflammation, necrosis, and total histological score gradually increase to reach peak levels at 48 h. Proenzymes and most plasma protease inhibitors decreased to low levels after 6-12 h followed by a gradual increase. The sequential changes over time indicate that kallikrein - kinin activation, and plasminogen activation are probably early events in cerulein-induced AP in rats, alpha(1)-Macroglobulin and (alpha(1-)protease inhibitor gradually decreased during the whole study period, probably being "second line" defense inhibitors. Levels above normal were seen for alpha(2)-antiplasmin and factor X at 48 h, normalizing at 72 h. Conclusions. These results suggest that protease activation and protease inhibitor consumption occur in cerulein-induced AP in the rat. (C) 1999 Academic Press.