title: Insulinlike growth factor I and interleukin 1 beta messenger RNA in a rat model of granulomatous enterocolitis and hepatitis.
abstract: BACKGROUND
  Insulinlike growth factor I (IGF-I) is mitogenic for fibroblasts and smooth muscle cells and stimulates collagen synthesis. The present study tested the hypothesis that IGF-I is important in the development of granulomatous inflammation and fibrosis.
  
  
  METHODS
  IGF-I messenger RNA (mRNA) was measured in bowel and liver of rats with peptidoglycan-polysaccharide-induced chronic granulomatous enterocolitis and hepatitis using RNase protection. Cellular sites of IGF-I mRNA and IGF-I peptide precursor were localized by in situ hybridization and immunohistochemistry, respectively. Sites of IGF-I synthesis were compared with sites of interleukin 1 beta mRNA expression.
  
  
  RESULTS
  IGF-I mRNA was increased 3.7-fold in cecal tissue from peptidoglycan-polysaccharide-injected rats compared with controls. IGF-I mRNA was up-regulated in fibroblastlike cells in the intensely fibrotic periphery of cecal and hepatic granulomas. This region also expressed IGF-I peptide precursor. Interleukin 1 mRNA localized to macrophage-like cells in the center of granulomas.
  
  
  CONCLUSIONS
  IGF-I may be important in the development of fibrosis in this model of Crohn's disease. The localization of IGF-I and interleukin 1 mRNAs to distinct but adjacent sites is consistent with a paracrine interaction between cells expressing IGF-I and interleukin 1.
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor.
authors.forename: E M
authors.initials: EM
authors.lastname: Zimmermann
authors.forename: R B
authors.initials: RB
authors.lastname: Sartor
authors.forename: R D
authors.initials: RD
authors.lastname: McCall
authors.forename: M
authors.initials: M
authors.lastname: Pardo
authors.forename: D
authors.initials: D
authors.lastname: Bender
authors.forename: P K
authors.initials: PK
authors.lastname: Lund
mesh_terms: D000818:Animals; D002432:Cecum / Q000378:metabolism; D004760:Enterocolitis / Q000378:metabolism*; D005260:Female; D006099:Granuloma / Q000378:metabolism*; D006520:Hepatitis, Animal / Q000378:metabolism*; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D007375:Interleukin-1 / Q000235:genetics*; D008099:Liver / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011917:Rats, Inbred Lew; D014018:Tissue Distribution
chemical_list: D007375:Interleukin-1; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I