title: The anti-fibrotic effects of epigallocatechin-3-gallate in bile duct-ligated cholestatic rats and human hepatic stellate LX-2 cells are mediated by the PI3K/Akt/Smad pathway.
abstract: OBJECTIVE
  (-)-Epigallocatechin-3-gallate (EGCG) is one of the most abundant polyphenols in green tea with strong antioxidant activity and various therapeutic effects. In this study, we investigated the anti-fibrotic effects of EGCG and underlying mechanisms in bile duct-ligated (BDL) rats and a liver fibrosis model in vitro.
  
  
  METHODS
  BDL rats were treated with EGCG (25 mg·kg(-1)·d(-1), po) for 14 d, and then the serum, bile and liver samples were collected. Liver fibrosis was assessed by serum, urine and bile biochemistry analyses and morphological studies of liver tissues. TGF-β1-stimulated human hepatic stellate LX-2 cells were used as a liver fibrosis model in vitro. The expression of liver fibrogenic genes and signaling proteins in the PI3K/Akt/Smad pathway was examined using Western blotting and/or real-time PCR.
  
  
  RESULTS
  In BDL rats, EGCG treatment significantly ameliorates liver necrosis, inflammation and fibrosis, and suppressed expression of the genes associated with liver inflammation and fibrogenesis, including TNF-α, IL-1β, TGF-β1, MMP-9, α-SMA, and COL1A1. In LX-2 cells, application of EGCG (10, 25 μmol/L) dose-dependently suppressed TGF-β1-stimulated expression of COL1A1, MMP-2, MMP-9, TGF-β1, TIMP1, and α-SMA. Furthermore, EGCG significantly suppressed the phosphorylation of Smad2/3 and Akt in the livers of BDL rats and in TGF-β1-stimulated LX-2 cells. Application of LY294002, a specific inhibitor of PI3K, produced similar effects as EGCG did in TGF-β1-stimulated LX-2 cells, but co-application of EGCG and LY294002 did not produce additive effects.
  
  
  CONCLUSIONS
  EGCG exerts anti-fibrotic effects in BDL rats and TGF-β1-stimulated LX-2 cells in vitro via inhibiting the PI3K/Akt/Smad pathway.
authors.affiliation: 1] Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China [2] Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu 610072, China.
authors.forename: Dong-ke
authors.initials: DK
authors.lastname: Yu
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
authors.forename: Cai-xia
authors.initials: CX
authors.lastname: Zhang
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
authors.forename: Shuang-shuang
authors.initials: SS
authors.lastname: Zhao
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
authors.forename: Sheng-hua
authors.initials: SH
authors.lastname: Zhang
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Internal Medicine and Liver Center, School of Medicine, Yale University, New Haven, CT 06520, USA.
authors.forename: Shi-ying
authors.initials: SY
authors.lastname: Cai
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
authors.forename: Rong-guang
authors.initials: RG
authors.lastname: Shao
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
authors.forename: Hong-wei
authors.initials: HW
authors.lastname: He
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D002392:Catechin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D002460:Cell Line; D002779:Cholestasis / Q000150:complications*; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D008103:Liver Cirrhosis / Q000150:complications* / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D051785:Smad Proteins / Q000378:metabolism
chemical_list: D051785:Smad Proteins; D002392:Catechin; C045651:epigallocatechin gallate; D051057:Proto-Oncogene Proteins c-akt
references.citation: J Hepatol. 2004 Jan;40(1):52-9
references.pmid: 14672614
references.citation: Mol Aspects Med. 2014 Jun;37:1-2
references.pmid: 24287163
references.citation: J Lab Clin Med. 2005 Jun;145(6):316-22
references.pmid: 15976760
references.citation: Int J Mol Med. 2005 Oct;16(4):677-81
references.pmid: 16142404
references.citation: Am J Pathol. 2006 Feb;168(2):410-22
references.pmid: 16436656
references.citation: Lab Invest. 2006 Jul;86(7):697-709
references.pmid: 16682975
references.citation: Acta Pharmacol Sin. 2006 Dec;27(12):1600-7
references.pmid: 17112415
references.citation: Toxicology. 2008 Dec 30;254(3):120-9
references.pmid: 18662740
references.citation: Chem Biol Interact. 2009 Dec 10;182(2-3):159-64
references.pmid: 19646978
references.citation: Cancer Prev Res (Phila). 2010 May;3(5):670-9
references.pmid: 20424128
references.citation: Dig Liver Dis. 2010 Jun;42(6):409-18
references.pmid: 20434968
references.citation: Toxicology. 2010 Jun 29;273(1-3):45-52
references.pmid: 20438794
references.citation: Gastroenterology. 2010 Nov;139(5):1481-96
references.pmid: 20849855
references.citation: Hepatology. 2011 Feb;53(2):548-57
references.pmid: 21274875
references.citation: Biochem Pharmacol. 2011 Dec 15;82(12):1807-21
references.pmid: 21827739
references.citation: Cancer Sci. 2012 Oct;103(10):1848-56
references.pmid: 22703643
references.citation: Cancer. 2013 Jan 15;119(2):363-70
references.pmid: 22760587
references.citation: Compr Physiol. 2013 Oct;3(4):1473-92
references.pmid: 24265236
references.citation: Eur J Nutr. 2014 Feb;53(1):187-99
references.pmid: 23515587
references.citation: Gut. 2005 Jan;54(1):142-51
references.pmid: 15591520