Abstract | BACKGROUND/AIMS: METHODS: We examined the gene expression of interstitial collagenase (MMP-13) in the progressive and recovery phase of experimental rat liver fibrosis induced by chronic CCl4 intoxication by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. In order to identify the cells expressing MMP-13 mRNA by in situ hybridization, immunohistochemistry was performed using serial sections. RESULTS: In normal rat liver, a faint band for MMP-13 mRNA was observed by RT-PCR, but not by in situ hybridization. The livers of rats treated with CCl4 for 4 weeks showed fatty metamorphosis but no definite fibrosis. Positive signals for MMP-13 mRNA were observed in scattered mesenchymal cells, within lobules which seem to be stellate cells from immunohistochemical staining. Once the fibrosis became prominent, the faint band for MMP-13 mRNA was detected only by RT-PCR and very few signals, if any, by in situ hybridization. On the other hand, in the recovery phase of liver fibrosis, gene expression of MMP-13 was markedly enhanced. Strong positive cells by in situ hybridization were observed mainly at the interface between the resolving fibrous septa and the parenchyma. Overlapping both images of in situ hybridization and immunohistochemical staining with the help of a computer revealed that some positive cells, but not all cells, were stellate cells stained with a-smooth muscle actin antibody. CONCLUSIONS: MMP-13 participates in the degradation of newly-formed matrix in the recovery from rat liver fibrosis more than in the remodeling of extracellular matrix for the formation of fibrosis. Hepatic stellate cells play a crucial role in MMP-13 production in the recovery from fibrosis, though not all stellate cells were positive for MMP-13 mRNA. Further investigation into gene expression of MMP-13 in recovery will lead to new strategies for the treatment of liver cirrhosis.
|
Authors | T Watanabe, M Niioka, S Hozawa, K Kameyama, T Hayashi, M Arai, A Ishikawa, K Maruyama, I Okazaki |
Journal | Journal of hepatology
(J Hepatol)
Vol. 33
Issue 2
Pg. 224-35
(Aug 2000)
ISSN: 0168-8278 [Print] Netherlands |
PMID | 10952240
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
|
Chemical References |
- Carbon Tetrachloride
- Collagenases
- Matrix Metalloproteinase 13
- Mmp13 protein, rat
|
Topics |
- Animals
- Carbon Tetrachloride
(toxicity)
- Collagenases
(genetics, metabolism)
- Gene Expression Regulation, Enzymologic
- Liver Cirrhosis, Experimental
(chemically induced, enzymology, physiopathology)
- Male
- Matrix Metalloproteinase 13
- Rats
- Rats, Wistar
- Reverse Transcriptase Polymerase Chain Reaction
|