Carbon tetrachloride (CCl(4)) accelerated development of non-alcoholic fatty liver disease (NAFLD)/steatohepatitis (NASH) in MS-NASH mice fed western diet supplemented with fructose (WDF)

BACKGROUND: Multiple murine models of nonalcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) have been established by using obesogenic diets and/or chemical induction. MS-NASH mouse (formally FATZO) is a spontaneously developed dysmetabolic strain that can progress from hepatosteatosis to moderate fibrosis when fed a western diet supplemented with 5% fructose (WDF). This study aimed to use carbon tetrachloride (CCl(4)) to accelerate and aggravate progression of NAFLD/NASH in MS-NASH mouse. METHODS: Male MS-NASH mice at 8 weeks of age were fed WDF for the entire study. Starting at 16 weeks of age, CCl(4) was intraperitoneally administered twice weekly at a dose of 0.2 mL/kg for 3 weeks or 0.08 mL/kg for 8 weeks. Obeticholic acid (OCA, 30 mg/kg, QD) was administered in both MS-NASH and C57Bl/6 mice fed WDF and treated with CCl(4) (0.08 mL/kg). RESULTS: WDF enhanced obesity and hepatosteatosis, as well as induced moderate fibrosis in MS-NASH mice similar to previous reports. Administration of CCl(4) accelerated liver fibrosis with increased bridging and liver hydroxyproline contents, but had no significant impact on liver steatosis and lipid contents. High dose CCl(4) caused high mortality and dramatic elevation of ALT and ASL, while low dose CCl(4) resulted in a moderate elevation of ALT and AST with low mortality. Compared to C57BI/6 mice with WDF and CCl(4) (0.08 mL/kg), MS-NASH mice had more prominent hepatosteatosis and fibrosis. OCA treatment significantly lowered liver triglycerides, steatosis and fibrosis in both MS-NASH and C57Bl/6 mice fed WDF with CCl(4) treatment. CONCLUSIONS: CCl(4) reduced induction time and exacerbated liver fibrosis in MS-NASH mice on WDF, proving a superior NASH model with more prominent liver pathology, which has been used favorably in pharmaceutical industry for testing novel NASH therapeutics.