title: [Role of extracellular signal-regulated kinase 1/2 on inhibition of N-acetyl-seryl-aspartyl-lysyl-proline on proliferation and collagen synthesis of cultured rat pulmonary fibroblasts induced by platelet-derived growth factor].
abstract: OBJECTIVE
  To investigate the role of extracellular signal-regulated kinase 1/2 on the inhibition of N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) on the proliferation and collagen synthesis of cultured rat pulmonary fibroblasts induced by platelet-derived growth factor (PDGF).
  
  
  METHODS
  Pulmonary fibroblasts were prepared from lungs of neonatal Wistar rats as described previously. Cells were divided into 4 groups: (1) control group (0.4% FBS group); (2) PDGF (10 ng/ml) stimulated group; (3) PD98059+PDGF group (25 micromol/L PD98059+10 ng/ml PDGF); (4) AcSDKP+PDGF group (10(-8) mol/L AcSDKP+10 ng/ml PDGF). All experiments were performed in the fourth passages. Metabolic activity of fibroblasts was observed by MTT, and expressions of type I and type III collagen were measured by immunocytochemistry and western blot. Expressions of phospho-ERK1/2 and ERK1/2 were detected by western blot.
  
  
  RESULTS
  Compared with control group, exposure of pulmonary fibroblasts to 10 ng/ml PDGF increased cell metabolic activity, expression of type I and type III collagen and phosphorylation of ERK1/2. 25 micromol/L PD98059 and AcSDKP both could inhibit the metabolic activity of pulmonary fibroblasts, type I and type III collagen synthesis and phosphorylation of ERK1/ 2 induced by PDGF, with significant differences (P < 0.05). AcSDKP+PDGF group compared with PDGF stimulated group, metabolic activity of pulmonary fibroblasts decreased to 77.4%. Immunocytochemistry result showed that in AcSDKP+PDGF group, expressions of type I and type III collagen decreased to 69.3% and 67.2% compared with those of PDGF stimulated group. Western blot result showed that in AcSDKP+PDGF group, expressions of type I and type III collagen decreased to 92.4% and 78.0%, phospho-ERK1/2 decreased to 83.5% compared with those of PDGF stimulated group, with significant differences (P < 0.05).
  
  
  CONCLUSIONS
  ERK1/2 plays an important role in the inhibition of AcSDKP on the proliferation and collagen synthesis of cultured rat pulmonary fibroblasts induced by PDGF.
authors.affiliation: North China Coal Medical College, Tangshan 063000, China.
authors.forename: Kun-Fei
authors.initials: KF
authors.lastname: Wu
authors.forename: Yang
authors.initials: Y
authors.lastname: Fang
authors.forename: Dan-Dan
authors.initials: DD
authors.lastname: Li
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Zhang
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Rui-Min
authors.initials: RM
authors.lastname: Wang
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D009842:Oligopeptides / Q000494:pharmacology; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D009842:Oligopeptides; D010982:Platelet-Derived Growth Factor; D003094:Collagen; C058504:goralatide