Dysregulation of the calpain-calpastatin system plays a role in the development of cerulein-induced acute pancreatitis in the rat.
Calpain, a calcium-dependent cytosolic cysteine protease, is implicated in a multitude of cellular functions but also plays a role in cell death. Recently, we have shown that two ubiquitous isoforms, termed micro-calpain and m-calpain, are expressed in rat pancreatic acinar cells and that calcium ionophore-induced calpain activation leads to acinar cell injury. On the basis of these observations, we have now investigated the role of both calpain forms and the endogenous calpain inhibitor calpastatin in acute pancreatitis. After treatment of rats either without or with calpain inhibitor Z-Val-Phe methyl ester (ZVP; 60 mg/kg i.p.), pancreatitis was induced by cerulein injections (10 microg/kg i.p.; 5 times at hourly intervals). Calpain activation and calpastatin expression in the pancreatic tissue were studied by Western blot analysis. Pancreatic injury was assessed by plasma amylase activity, pancreatic wet/dry weight ratio (edema), histological and electron-microscopic analyses, as well as fluorescence labeling of actin filaments. Cerulein caused an activation of both micro-calpain and m-calpain, accompanied by degradation of calpastatin. Prophylactic administration of ZVP reduced the cerulein-induced calpain activation but had no effect on calpastatin alterations. In correlation to the diminished calpain activity, the severity of pancreatitis decreased as indicated by a decline in amylase activity (P < 0.01), pancreatic edema formation (P < 0.05), histological score for eight parameters (P < 0.01), and actin filament alterations. Our findings support the hypothesis that dysregulation of the calpain-calpastatin system may play a role in the onset of acute pancreatitis.
Weber
Heike
H
Institute of Clinical Chemistry and Pathobiochemistry, University of Rostock, Germany. heike.weber@med.uni-rostock.de
Jonas
Ludwig
L
Hühns
Saskia
S
Schuff-Werner
Peter
P
D000208:Acute Disease; D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002154:Calpain / Q000378:metabolism*; D002108:Ceruletide / Q000378:metabolism* / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D004789:Enzyme Activation; D005260:Female; D010179:Pancreas / Q000378:metabolism; D010195:Pancreatitis / Q000209:etiology* / Q000473:pathology; D051381:Rats; D011917:Rats, Inbred Lew; D012720:Severity of Illness Index
D002135:Calcium-Binding Proteins; D004151:Dipeptides; C095174:N-benzyloxycarbonyl-valyl-phenylalanine methyl ester; C033668:calpastatin; D002108:Ceruletide; D002154:Calpain; C449000:m-calpain; C449002:mu-calpain