Abstract
Hepatic stellate cells (HSC) play a pivotal role in liver fibrosis, and the clearance of activated HSC by apoptosis is associated with the resolution of liver fibrosis. The development of strategies that promote this process in a selective way is therefore important. We evaluated the effects of indole-3-carbinol (I3C), a nutritional component derived from vegetables from the Brassica family, on liver fibrosis and HSC apoptosis. The in vivo therapeutic effects of I3C were monitored in three rat models of liver fibrosis induced by porcine serum, bile duct ligation, or multiple hepatotoxic factors, and its proapoptotic effect and molecular mechanism were studied in vitro in HSC-T6, a rat HSC line. The results showed that I3C treatment significantly reduced the number of activated HSC in the livers of rats with liver fibrosis. In histopathology, I3C reduced hepatocyte degeneration and necrosis, accelerated collagen degradation, and promoted the reversal of liver fibrosis. I3C prescribed to HSC-T6 resulted in morphologic alterations typical of apoptosis and DNA cleavage to a nucleosomal ladder. Moreover, I3C significantly increased the HSC-T6 apoptosis rate and the expression ratio of Bax to Bcl-2. High-throughput protein array analysis indicated that the tumor necrosis factor-α/nuclear factor-κB (NF-κB) signal pathway participated in I3C-induced HSC-T6 apoptosis. Western blot and electrophoretic mobility-shift assay confirmed that I3C inhibited the phosphorylation of inhibitor of κB kinase α and inhibitor of κB-α and NF-κB DNA binding activity. In conclusion, I3C could promote the reverse process of liver fibrosis in vivo and induce apoptosis of activated HSC in vitro, which indicates the use of I3C as a potential therapeutic agent in liver fibrosis treatment.
Footnotes
This work was supported by the National Nature Science Foundation of China [Grants 30800931, 30371666] and the Natural Science Foundation of Hubei Province, China [Grant 2008CDB117].
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.111.179820.
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ABBREVIATIONS:
- ECM
- extracellular matrix
- HSC
- hepatic stellate cells
- α-SMA
- α-smooth muscle actin
- I3C
- indole-3-carbinol
- IKKα
- inhibitor of κB kinase α
- p-IKKα
- phospho-IKKα
- IκB-α
- inhibitor of κB-α
- p-IκB-α
- phospho-IκB-α
- NF-κB
- nuclear factor-κB
- DMSO
- dimethyl sulfoxide
- DMEM
- Dulbecco's modified Eagle's medium
- FBS
- fetal bovine serum
- TNFα
- tumor necrosis factor-α
- PS
- porcine serum
- BDL
- bile duct ligation
- MHT
- multiple hepatotoxic
- PBS
- phosphate-buffered saline
- HE
- hematoxylin and eosin
- GAPDH
- glyceraldehyde-3-phosphate dehydrogenase
- EMSA
- electrophoretic mobility-shift assay
- FITC
- fluorescein isothiocyanate
- DIM
- 3,3′-diindolylmethane
- PCR
- polymerase chain reaction.
- Received January 24, 2011.
- Accepted August 19, 2011.
- Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics
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