A glycyrrhizin-containing preparation reduces hepatic steatosis induced by hepatitis C virus protein and iron in mice

Abstract

A European randomized trial showed biochemical effects of 6-month treatment with Stronger Neo-Minophagen C (SNMC), a glycyrrhizin-containing preparation, in patients with chronic hepatitis C, but its underlying mechanisms remain elusive. We reported previously that SNMC exhibits an anti-oxidative effect in hepatitis C virus (HCV) transgenic mice that develop marked hepatic steatosis with mitochondrial injury under iron overloading. Hepatic steatosis and iron overload are oxidative stress-associated pathophysiological features in chronic hepatitis C. The aim of this study was to investigate whether long-term treatment with SNMC could prevent the development of hepatic steatosis in iron-overloaded HCV transgenic mice. C57BL/6 transgenic mice expressing the HCV polyprotein were fed an excess iron diet concomitantly with intraperitoneal injection of saline, SNMC, or seven-fold-concentrated SNMC thrice weekly for 6 months. Stronger Neo-Minophagen C inhibited the development of hepatic steatosis in a dose-dependent manner without affecting hepatic iron content, attenuated ultrastructural alterations of mitochondria of the liver, activated mitochondrial β-oxidation with increased expression of carnitine palmitoyl transferase I and decreased the production of reactive oxygen species in the liver in iron-overloaded transgenic mice. However, SNMC hardly affected the unfolded protein response, which post-transcriptionally activates sterol regulatory element-binding protein 1, a transcription factor involved in lipid synthesis, even though we reported previously the activation of the unfolded protein response in the same iron-overloaded transgenic mice. These results suggest that SNMC prevents hepatic steatosis possibly by protecting mitochondria against oxidative stress induced by HCV proteins and iron overload.