title: [Salvianolic acid B inhibits ERK signal transduction pathway activated by transforming growth factor-β1 in rat hepatic stellate cells].
abstract: OBJECTIVE
  To investigate the effects of salvianolic acid B (SA-B) on extracellular signal-regulated kinase (ERK) signal transduction pathway activated by transforming growth factor-β1 (TGF-β1) in rat hepatic stellate cells (HSCs).
  
  
  METHODS
  HSCs were isolated from male Sprague-Dawley rats by in situ perfusion and Nycodenz density-gradient centrifugation method. TGF-β1 and SA-B were directly added to the serum-free medium of HSCs. Total and phosphorylated ERK, MEK, Raf and α-smooth muscle actin (α-SMA) and type I collagen were assayed by Western blotting.
  
  
  RESULTS
  Phosphorylation of MEK in HSCs with or without TGF-β1 was inhibited by SA-B; however, phosphorylation of Raf in HSCs with or without TGF-β1 was not inhibited by SA-B. Expression of α-SMA in HSCs with TGF-β1 was inhibited by SA-B. Combination of SA-B and the inhibitors of ERK (PD98059) can effectively inhibit the expression of α-SMA. SA-B also inhibited synthesization of type I collagen in HSCs with or without TGF-β1.
  
  
  CONCLUSIONS
  The action point of SA-B inhibiting ERK signaling induced by TGF-β1 in HSCs is the inhibition of the phosphorylation of MEK. SA-B reduces the increase of expression of α-SMA and protein synthesization of type I collagen induced by TGF-β1 by means of inhibiting ERK signaling in activated HSCs of rats.
authors.affiliation: Department of Liver Cirrhosis, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
authors.forename: Ya-fang
authors.initials: YF
authors.lastname: Song
authors.forename: Zhi-gang
authors.initials: ZG
authors.lastname: Lü
authors.forename: Lie-ming
authors.initials: LM
authors.lastname: Xu
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001572:Benzofurans / Q000494:pharmacology*; D024042:Collagen Type I / Q000096:biosynthesis; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D055166:Hepatic Stellate Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D053630:Depsides
chemical_list: D000199:Actins; D001572:Benzofurans; D024042:Collagen Type I; D048049:Extracellular Signal-Regulated MAP Kinases; D053773:Transforming Growth Factor beta1; C498862:Acta2 protein, rat; C076944:salvianolic acid B; D053630:Depsides