title: Inhibitory effect of cyclosporin A on growth and collagen synthesis of rat cardiac fibroblasts induced by arginine vasopressin.
abstract: OBJECTIVE
  To investigate the effects of cyclosporin A (CsA) on growth and collagen synthesis of cardiac fibroblasts (CFs) induced by arginine vasopressin (AVP).
  
  
  METHODS
  CFs of neonatal Sprague-Dawley rats were isolated by trypsinization and cultured; growth-arrested CFs were stimulated with 1 x 10(-7) mol x L(-1) AVP in the presence or absence of CsA (0.05, 0.5 and 5 micromol x L(-1)). MTT and flow cytometry techniques were adopted to measure cell number and analyze cell cycle respectively. Collagen synthesis was determined by measurement of hydroxyproline content in culture supernatant with colorimetry. Calcineurin activity was estimated by chemiluminescence. Trypan blue staining to test the viability of CFs.
  
  
  RESULTS
  0.05, 0.5 and 5 micromol x L(-1) CsA inhibited the increase of CFs number induced by 1 x 10(-7) mol x L(-1) AVP in a dose-dependent manner, with the inhibitory rates by 12%, 24% and 29%, respectively (P < 0.05). Furthermore, cell cycle analysis showed 0.5 micromol x L(-1) CsA decreased the S stage percentage and proliferation index of CFs stimulated by AVP (P < 0.05). In culture medium, the hydroxyproline content induced by AVP decreased by 0.5 and 5 micromol x L(-1) CsA (P < 0.05), with the inhibitory rates of 29% and 33%, respectively. CsA completely inhibited the increment of calcineurin activity induced by AVP (P < 0.01), but CsA itself had no effect on the baseline of calcineurin activity and CFs viability.
  
  
  CONCLUSIONS
  CsA inhibits proliferation and collagen synthesis of CFs by virtue of blocking calcineurin signaling pathway and might provide a novel target for prevention and treatment to cardiac fibrosis.
authors.affiliation: Department of Cardiology, Tangdu Hospital, The Fourth Military Medical University, Xi' an 710038, China.
authors.forename: Fu-jun
authors.initials: FJ
authors.lastname: Shang
authors.forename: Lian-you
authors.initials: LY
authors.lastname: Zhao
authors.forename: Qiang-sun
authors.initials: QS
authors.lastname: Zheng
authors.forename: Jie-pin
authors.initials: JP
authors.lastname: Wang
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001127:Arginine Vasopressin / Q000494:pharmacology*; D019703:Calcineurin / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis*; D016572:Cyclosporine / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006909:Hydroxyproline / Q000378:metabolism; D009206:Myocardium / Q000166:cytology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001127:Arginine Vasopressin; D016572:Cyclosporine; D003094:Collagen; D019703:Calcineurin; D006909:Hydroxyproline