title: The naïve effector cells of collagen type I during acute experimental pancreatitis are acinar cells and not pancreatic stellate cells.
abstract: OBJECTIVE
  The purpose of this study was to investigate the expression of collagen type I and the mRNA level of its regulatory factor, TGF-β1, in tissue samples of acute pancreatitis and to determine the significance of collagen type I in predisposition to pancreatic fibrosis during acute pancreatitis.
  
  
  METHODS
  Sprague-Dawley rats were divided into an experimental group (30 rats) and a control group (12 rats). The rats in the experimental group were intraperitoneally injected with cerulein to induce acute pancreatitis. The distribution and expression of collagen type I in the pancreatic tissues were examined by immunohistochemical staining. The mRNA level of TGF-β1 was determined by real-time polymerase chain reaction (PCR).
  
  
  RESULTS
  (1) Collagen type I was localized in the cytoplasm of pancreatic acinar cells. With pancreatitis progressed, strong positive staining for collagen type I covered whole pancreatic lobules, whereas, the islet tissue, interlobular area, and pancreatic necrotic area were negative for collagen type I. (2) The level of TGF-β1 mRNA in rats from the experimental group increased gradually the establishment of acute pancreatitis, and was significantly higher than that in the control group at every time point.
  
  
  CONCLUSIONS
  (1) During acute pancreatitis, pancreatic acinar cells, not pancreatic stellate cells as traditionally believed, were the naïve effector cells of collagen type I. (2) TGF-β1 played a key role in regulating collagen I expression during acute pancreatitis.
authors.affiliation: Department of General Surgery, The People's Liberation Army General Hospital of Chengdu Command, Chengdu 610083, Sicuan Province, China. Electronic address: cdgjq123@126.com.
authors.forename: JiaQing
authors.initials: J
authors.lastname: Gong
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Jiang
authors.forename: GuoHu
authors.initials: G
authors.lastname: Zhang
authors.forename: FuZhou
authors.initials: F
authors.lastname: Tian
mesh_terms: D061354:Acinar Cells / Q000378:metabolism* / Q000473:pathology; D000208:Acute Disease; D000818:Animals; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D005260:Female; D008297:Male; D058954:Pancreatic Stellate Cells / Q000378:metabolism* / Q000473:pathology; D010195:Pancreatitis / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism
chemical_list: D024042:Collagen Type I; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1
keywords: AP; Acinar cells; Acute pancreatitis; CP; Collagen type I; ECM; PCR; PSCs; TGF; TGF-β1; acute pancreatitis; chronic pancreatitis; pancreatic stellate cells; polymerase chain reaction; synthesize extracellular matrix; transforming growth factor