Nrf2 and Snail-1 in the prevention of experimental liver fibrosis by caffeine

World J Gastroenterol. 2013 Dec 21;19(47):9020-33. doi: 10.3748/wjg.v19.i47.9020.


Aim: To determine the molecular mechanisms involved in experimental hepatic fibrosis prevention by caffeine (CFA).

Methods: Liver fibrosis was induced in Wistar rats by intraperitoneal thioacetamide or bile duct ligation and they were concomitantly treated with CFA (15 mg/kg per day). Fibrosis and inflammatory cell infiltrate were evaluated and classified by Knodell index. Inflammatory infiltrate was quantified by immunohistochemistry (anti-CD11b). Gene expression was analyzed by quantitative reverse transcription-polymerase chain reaction for collagen I (Col-1), connective tissue growth factor (CTGF), transforming growth factor β1 (TGF-β1), tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), IL-6, superoxide dismutase (SOD) and catalase (CAT). Activation of Nrf2 and Snail-1 was analyzed by Western-blot. TNF-α expression was proved by enzyme-linked immunosorbant assay, CAT activity was performed by zymography.

Results: CFA treatment diminished fibrosis index in treated animals. The Knodell index showed both lower fibrosis and necroinflammation. Expression of profibrogenic genes CTGF, Col-1 and TGF-β1 and proinflammatory genes TNF-α, IL-6 and IL-1 was substantially diminished with CFA treatment with less CD11b positive areas. Significantly lower values of transcriptional factor Snail-1 were detected in CFA treated rats compared with cirrhotic rats without treatment; in contrast Nrf2 was increased in the presence of CFA. Expression of SOD and CAT was greater in animals treated with CFA showing a strong correlation between mRNA expression and enzyme activity.

Conclusion: Our results suggest that CFA inhibits the transcriptional factor Snail-1, down-regulating profibrogenic genes, and activates Nrf2 inducing antioxidant enzymes system, preventing inflammation and fibrosis.

Keywords: Antioxidant enzymes; Bile duct ligation; Caffeine; Liver fibrosis; Profibrogenic genes; Proinflammatory cytokines; Thioacetamide.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bile Ducts / surgery
  • Biomarkers / metabolism
  • CD11b Antigen / metabolism
  • Caffeine / pharmacology*
  • Catalase / genetics
  • Catalase / metabolism
  • Collagen Type I / genetics
  • Connective Tissue Growth Factor / genetics
  • Cytoprotection
  • Gene Expression Regulation
  • Interleukin-1 / genetics
  • Interleukin-6 / genetics
  • Ligation
  • Liver / drug effects*
  • Liver / metabolism
  • Liver / pathology
  • Liver Cirrhosis, Experimental / etiology
  • Liver Cirrhosis, Experimental / genetics
  • Liver Cirrhosis, Experimental / metabolism
  • Liver Cirrhosis, Experimental / pathology
  • Liver Cirrhosis, Experimental / prevention & control*
  • Male
  • NF-E2-Related Factor 2 / metabolism*
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Signal Transduction / drug effects
  • Snail Family Transcription Factors
  • Superoxide Dismutase / genetics
  • Thioacetamide
  • Transcription Factors / metabolism*
  • Transforming Growth Factor beta1 / genetics
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism


  • Biomarkers
  • CCN2 protein, rat
  • CD11b Antigen
  • Collagen Type I
  • Interleukin-1
  • Interleukin-6
  • NF-E2-Related Factor 2
  • Nfe2l2 protein, rat
  • RNA, Messenger
  • Snai2 protein, rat
  • Snail Family Transcription Factors
  • Tgfb1 protein, rat
  • Transcription Factors
  • Transforming Growth Factor beta1
  • Tumor Necrosis Factor-alpha
  • Thioacetamide
  • Connective Tissue Growth Factor
  • Caffeine
  • Catalase
  • Superoxide Dismutase