title: [Erythropoietin suppresses the expressions of TGF-beta1 and collagen in rat cardiac fibroblasts induced by angiotensin II].
abstract: OBJECTIVE
  Recent studies have shown cardiac protection effects of erythropoietin (EPO). The present experiment was designed to investigate the effects of EPO on TGF-beta1, nitric oxide synthase (NOS), collagen contents induced by angiotensin II (Ang II) in rat cardiac fibroblasts (CFs) and explore the roles of PI3-K/Akt signaling pathway on related effects.
  
  
  METHODS
  Neonatal rat CFs was isolated by collagenase and trypsinase digestion methods. PBS, EPO, Ang II in the absence or presence of LY294002, an inhibitor of PI3-K, or L-NAME, an inhibitor of NOS, were added to CFs and cultured for 24 hours. The concentration of collagen I and collagen III in culture medium were quantitated by ELISA. The levels of nitric oxide (NO) and the activities of NOS as well as NOS isoforms were measured by chemical enzymic method. Western blot was applied to detecting the protein expressions of Akt, p-Akt, eNOS, iNOS, and TGF-beta1.
  
  
  RESULTS
  The concentrations of collagen I and collagen III in CFs culture medium were significantly increased while the level of NO was significantly decreased by Ang II and these changes were significantly suppressed by EPO in a dose dependent manner. The effects of EPO on eNOS and NO could be blocked by LY294002. L-NAME could block EPO's effect on NO but not on the eNOS expression. The suppression effects on expressions of TGF-beta1 and collagen by Ang II in CFs were blocked by both LY294002 and L-NAME.
  
  
  CONCLUSIONS
  EPO suppresses the upregulated expressions of TGF-beta1 and increased production of collagen induced by Ang II through activating the PI3-K/Akt signaling pathway in neonatal rat CFs.
authors.affiliation: Department of Cardiology, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Xin-Jin
authors.initials: XJ
authors.lastname: Zhang
authors.forename: Ye-Xin
authors.initials: YX
authors.lastname: Ma
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wen
authors.forename: Xue-Jing
authors.initials: XJ
authors.lastname: Xu
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism*; D004921:Erythropoietin / Q000494:pharmacology*; D032386:Myoblasts, Cardiac / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D053773:Transforming Growth Factor beta1; D004921:Erythropoietin; D000804:Angiotensin II; D003094:Collagen