Green tea polyphenols (GTPS) reduced fibrogenesis in non-alcoholic fatty liver disease in rats

Abstract

Background: Attention has been focused on the use of supple-mentary phytochemicals in the treatment of non-alcoholic fattyliver disease (NAFLD). Objective: We investigated whetherEGCG could modulate expression of profibrogenic markers inNAFLD. Experimental Design: We fed an unsaturated fat diet(30% fish oil) to female Sprague-Dawley rats (180-200g), con-sumed ad libitum for 8 weeks (NAFLD; n = 8). Control animals(CF; n = 8) were fed an isocaloric diet with commercial ratchow. To evaluate the effect of EGCG on NAFLD, rats in theNAFLD group was injected with EGCG intraperitoneally[50mg/kg] three times per week. The CF group received thevehicle. At killing, blood and liver samples were collected forserum alanine aminotransferase (ALT), histology and molecularanalysis. Each histological sample was evaluated for fatty liver(graded from 0-4+), necrosis (number of necrotic foci(no./mm2) and inflammation (cells per mm2). The amount ofcollagen formation was estimated using Sirius Red staining.Reverse transcription polymerase chain reaction (RT-PCR) wascarried out for TGF-β1, procollagen-I (Pro-col-I), tissue inhibitorsof metalloproteinases (TIMP-1, TIMP-2) matrix metalloproteinase(MMP-2). Zymography determined the enzyme activity of MMP-2. Electrophoretic mobility shift assay was performed fornuclear factor-kappa B (NF-kB) activity. Results: NAFLD rats hada significantly higher serum ALT level, fatty liver, necrosis,inflammation and amount of collagen formation (Sirius Redstaining) when compared with the CF rats (p< 0.05). ThemRNA levels of the profibrotic factors, TGF-β1, Pro-col-I, TIMP-1, TIMP-2 and MMP-2 were elevated in the NAFLD group (p<0.05). The MMP-2 enzyme and NF-kB activity were alsoincreased in the NAFLD rats (p<0.01). Treatment with EGCGsignificantly reduced the severity of pathological changeswhich include fatty change, necrosis and inflammation, fibrosis(Sirius Red) and down-regulated expression of TGF-β1, Pro-col-I, TIMP-1, TIMP-2 and MMP-2. Treatment with EGCG also sig-nificantly decreased the MMP-2 enzyme and NF-kB activity.Conclusion: EGCG decreased the degree of hepatic fibrosisand profibrogenic markers in rats fed with fish and dextrose.We proposed that the therapeutic effect of GTPs in NAFLD maybe mediated through down-regulation of profibrogenic factorsand its use can be considered as adjuvant therapy in fiborgenicliver disease.