Hydrogen Rich Water Prevents Progression of NASH and Accompanying Hepatic Tumorigenesis in Mice

Abstract

(Background/Aims) Non-alcoholic fatty liver disease (NAFLD) is one of the common causes of chronic liver disease and a major sign of metabolic syndrome. Non-alcoholic steatohepatitis(NASH) is a more severe form of NAFLD and is broadly defined by the presence of steatosis with inflammation and progressive fibrosis, and can ultimately lead to cirrhosis and hepatocellular carcinoma (HCC). The prevalence of NAFLD is gradually increasing. It is known that the presence of reactive oxygen stress (ROS) plays important role for the onset of NASH. Molecular hydrogen has recently been shown to have therapeutic value as an antioxidant through its ability to reduce cytotoxic ROS. Therefore, it may be of potential therapeutic in the treatment of ROS-induced pathologies. However, there is no report that demonstrates the effects of hydrogen for chronic liver disease such as NASH. In this study, we evaluated the effects of hydrogen rich water in the NASH model mouse. (Method) A methionine-choline-deficient (MCD) diet mouse NASH model was introduced. Eight-weekold C57BL/6 mice were divided into 3 experimental groups and fed for 8 weeks as follows : (1) MCD diet + normal water (NW group) (2) MCD diet + hydrogen rich water (HW group) (3) MCD diet mixed with 0.01% of the PPAR-agonist pioglitazone + normal water (PGZ group). Hepatic inflammatory grade and fibrosis stage of each group was compared histologically. Hepatic 8-OHdG concentrationwasmeasured by commercially available ELISA kit. Real time PCR was administered for quantifying the expression of hepatic inflammation genes such as TNF-α and IL-6, and lipogenic genes such as fatty acid synthase (FAS), fatty acid translocase (FAT), and fatty acid transport protein (FATP). Next, a STAM mouse NASH hepatocellular carcinoma model (purchased from Charles River Laboratories Japan Inc.) was introduced. This model mice were divided into 2 experimental groups and fed for 8 weeks as follows: (1) High fat ( HF ) diet + normal water (NW-STAM group) (2) HF diet + hydrogen rich water (HW-STAM group). After 8 weeks, mice were sacrificed and counted for hepatic tumor number. (Results) HW group and PGZ group showed low inflammation and fibrosis compared with NW group histologically. The concentration of 8-OHdG was reduced in HW and PGZ group compared with NW group. The hepatic mRNA expression of TNF-α, IL-6, FAS, FAT, and FATP were also downregulated in HW and PGZ groups. Hepatic tumor number was reduced in HW-STAM group compared with NW-STAM group. (Conclusion) Hydrogen rich water reduces hepatic lipogenesis, oxidative stress and results in improvement of NASH and accompanying hepatic tumors.