ABSTRACT
BACKGROUND AND AIMS: Liver fibrosis is the excessive accumulation of extracellular matrix proteins, including collagen, which occurs in most types of chronic liver diseases. Advanced liver fibrosis results in cirrhosis, liver failure, and portal hypertension. Activated hepatic perivascular stellate cells, portal fibroblasts, and myofibroblasts of bone marrow origin have been identified as major collagen-producing cells in the injured liver. These cells are activated by fibrogenic cytokines, such as TGF-ß1. The inhibition of TGF-ß1 function or synthesis is a major target for the development of antifibrotic therapies. Our previous study showed that the water and ethanol extracts of Graptopetalum paraguayense (GP), a Chinese herbal medicine, can prevent dimethylnitrosamine (DMN)-induced hepatic inflammation and fibrosis in rats. METHODS: We used rat hepatic stellate HSC-T6 cells and a diethylnitrosamine (DEN)-induced rat liver injury model to test the potential mechanism of GP extracts and its fraction, HH-F3. RESULTS: We demonstrated that GP extracts and HH-F3 downregulated the expression levels of extracellular matrix (ECM) proteins and inhibited the proliferation and migration via suppression of the TGF-ß1 pathway in rat hepatic stellate HSC-T6 cells. Moreover, the HH-F3 fraction decreased hepatic collagen content and reduced plasma AST, ALT, and γ-GT activities in a DEN-induced rat liver injury model, suggesting that GP/HH-F3 has hepatoprotective effects against DEN-induced liver fibrosis. CONCLUSION: These findings indicate that GP/HH-F3 may be a potential therapeutic agent for the treatment of liver fibrosis. The inhibition of TGF-ß-mediated fibrogenesis may be a central mechanism by which GP/HH-F3 protects the liver from injury.
Subject(s)
Crassulaceae/chemistry , Liver Cirrhosis/drug therapy , Plant Extracts/therapeutic use , Transforming Growth Factor beta/metabolism , Animals , Cell Line , Collagen/genetics , Collagen/metabolism , Extracellular Matrix Proteins/genetics , Extracellular Matrix Proteins/metabolism , Hepatic Stellate Cells/drug effects , Hepatic Stellate Cells/metabolism , Humans , Liver Cirrhosis/metabolism , Plant Extracts/pharmacology , Rats , Rats, Wistar , Signal Transduction , Transforming Growth Factor beta/geneticsABSTRACT
Plectranthus amboinicus (P. amboinicus) is a folk herb that is used to treat inflammatory diseases or swelling symptoms in Taiwan. We investigated therapeutic efficacy of P. amboinicus in treating Rheumatoid Arthritis (RA) using collagen-induced arthritis animal model. Arthritis was induced in Lewis rats by immunization with bovine type II collagen. Serum anti-collagen IgG, IgM and C-reactive protein (CRP) were analyzed. To understand the inflammation condition of treated animals, production of TNF-α, IL-6 and IL-1ß from peritoneal exudates cells (PEC) were also analyzed. P. amboinicus significantly inhibited the footpad swelling and arthritic symptoms in collagen-induced arthritic rats, while the serum anti-collagen IgM and CRP levels were consistently decreased. The production of pro-inflammatory cytokines TNF-α, IL-6 and IL-1ß were also decreased in the high dosage of P. amboinicus group. Here, we demonstrate the potential anti-arthritic effect of P. amboinicus for treating RA, which might confer its anti-rheumatic activity. This differs the pharmacological action mode of indomethacin.
