Antifibrotic effects of green tea on in vitro and in vivo models of liver fibrosis.
OBJECTIVE
To examine the protective effect of green tea extract (GT) on hepatic fibrosis in vitro and in vivo in dimethylnitrosamine (DMN)-induced rats.


METHODS
HSC-T6, a rat hepatic stellate cell line, was used as an in vitro assay system. Cell proliferation, collagen content, and type 1 collagen expression were examined in activated HSC-T6 cells. Collagen was determined by estimating the hydroxyproline content. In rats with DMN-induced hepatic fibrosis, serum aspartate aminotransferase and alanine aminotransferase concentrations, liver hydroxyproline and lipid peroxides were determined. Pathologic changes were examined by hematoxylin & eosin staining.


RESULTS
GT administration prevented the development of hepatic fibrosis in the rat model of DMN-induced liver fibrosis. These results were confirmed both by liver histology and by quantitative measurement of hepatic hydroxyproline content, a marker of liver collagen deposition. Accordingly, inhibition of proliferation, reduced collagen deposition, and type 1 collagen expression were observed in activated HSC-T6 cells following GT treatment. These results imply that GT reduced the proliferation of activated HSC and down regulated the collagen content and expression of collagen type 1, thereby ameliorating hepatic fibrosis.


CONCLUSIONS
This study demonstrates that green tea administration can effectively improve liver fibrosis caused by DMN, and may be used as a therapeutic option and preventive measure against hepatic fibrosis.
Kim
Hye-Kyung
HK
Department of Food and Biotechnology, College of Science and Technology, Korea University, Jochiwon, Chungnam 339-700, South Korea.
Yang
Taik-Hoon
TH
Cho
Hong-Yon
HY
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D024042:Collagen Type I / Q000378:metabolism; D004128:Dimethylnitrosamine; D004195:Disease Models, Animal; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006909:Hydroxyproline / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000473:pathology* / Q000517:prevention & control*; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D011919:Rats, Inbred Strains; D013662:Tea; D016896:Treatment Outcome
D024042:Collagen Type I; D008054:Lipid Peroxides; D010936:Plant Extracts; D013662:Tea; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D004128:Dimethylnitrosamine; D006909:Hydroxyproline