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OPEN
received: 08 March 2015 accepted: 14 July 2015 Published: 11 August 2015
Seven weeks of Western diet in apolipoprotein-E-deficient mice induce metabolic syndrome and non-alcoholic steatohepatitis with liver fibrosis Robert Schierwagen1,*, Lara Maybüchen1,*, Sebastian Zimmer2, Kanishka Hittatiya3, Christer Bäck4, Sabine Klein1, Frank E Uschner1, Winfried Reul1, Peter Boor5,6, Georg Nickenig2, Christian P Strassburg1, Christian Trautwein4, Jogchum Plat7, Dieter Lütjohann8, Tilman Sauerbruch1, Frank Tacke4 & Jonel Trebicka1 Non-alcoholic steatohepatitis (NASH) is characterised by hepatic steatosis, inflammation and fibrosis, which might progress to cirrhosis. Human NASH is associated with metabolic syndrome (MS). Currently, rodent NASH models either lack significant fibrosis or MS. ApoE−/− mice are a MS model used in cardiovascular research. The aim of this work was to establish and characterise a novel mouse NASH model with significant fibrosis and MS. ApoE−/− and wild-type mice (wt) were fed either a western-diet (WD), methionine-choline-deficient-diet (MCD) or normal chow. Liver histology, RT-PCR, hepatic hydroxyproline content, triglycerides and cholesterol levels, and fasting glucose levels assessed hepatic steatosis, inflammation and fibrosis. Further, portal pressure was measured invasively, and kidney pathology was assessed by histology. ApoE−/− mice receiving WD showed abnormal glucose tolerance, hepatomegaly, weight gain and full spectrum of NASH including hepatic steatosis, fibrosis and inflammation, with no sign of renal damage. MCD-animals showed less severe liver fibrosis, but detectable renal pathological changes, besides weight loss and unchanged glucose tolerance. This study describes a murine NASH model with distinct hepatic steatosis, inflammation and fibrosis, without renal pathology. ApoE−/− mice receiving WD represent a novel and fast model with all characteristic features of NASH and MS well suitable for NASH research.
Non-alcoholic fatty liver disease (NAFLD) covers a wide spectrum of diseases ranging from mere steatosis to non-alcoholic stetatohepatitis (NASH) with possible progression to cirrhosis1. NAFLD is characterised by the metabolic syndrome, dyslipidemia, insulin resistance and obesity2,3, and associated with increased liver-related mortality4. The pathogenesis of NAFLD is poorly understood. Besides the “two-hit”-model which states that after the first damage (steatosis), further damage, such as oxidative stress and subsequent inflammation, leads to NASH5, several additional hypotheses on initiation and 1
Department of Internal Medicine I, University of Bonn, Germany. 2Department of Internal Medicine II, University of Bonn, Germany. 3Institute of Pathology, University of Bonn, Germany. 4Department of Internal Medicine III, RWTH University of Aachen, Germany. 5Division of Nephrology, RWTH University of Aachen, Germany. 6Institute of Pathology, RWTH University of Aachen, Germany. 7Department of Human Biology, University of Maastricht, Netherlands. 8Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Germany. *These authors contributed equally to this work. Correspondence and requests for materials should be addressed to J.T. (email: [email protected]) Scientific Reports | 5:12931 | DOI: 10.1038/srep12931
1
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Figure 1. Study design and general characteristics. (A) Schematic overview of the study design. wt and ApoE−/− mice were fed either with normal chow, high-fat Western diet (WD) rich in cholesterol or methionine and choline deficient diet (MCD) for seven weeks. (B) Body weight of animals before they were sacrificed. ApoE−/− mice fed with WD showed a significant increase in body weight, while mice fed with MCD diet showed a decrease in body weight. (C) Relative liver weight (in % of body weight) in ApoE−/− mice fed with WD was increased, suggesting hepatomegaly, whereas it was not altered in mice fed with MCD diet. Graphs are expressed as means ± standard deviation. p
OPEN
received: 08 March 2015 accepted: 14 July 2015 Published: 11 August 2015
Seven weeks of Western diet in apolipoprotein-E-deficient mice induce metabolic syndrome and non-alcoholic steatohepatitis with liver fibrosis Robert Schierwagen1,*, Lara Maybüchen1,*, Sebastian Zimmer2, Kanishka Hittatiya3, Christer Bäck4, Sabine Klein1, Frank E Uschner1, Winfried Reul1, Peter Boor5,6, Georg Nickenig2, Christian P Strassburg1, Christian Trautwein4, Jogchum Plat7, Dieter Lütjohann8, Tilman Sauerbruch1, Frank Tacke4 & Jonel Trebicka1 Non-alcoholic steatohepatitis (NASH) is characterised by hepatic steatosis, inflammation and fibrosis, which might progress to cirrhosis. Human NASH is associated with metabolic syndrome (MS). Currently, rodent NASH models either lack significant fibrosis or MS. ApoE−/− mice are a MS model used in cardiovascular research. The aim of this work was to establish and characterise a novel mouse NASH model with significant fibrosis and MS. ApoE−/− and wild-type mice (wt) were fed either a western-diet (WD), methionine-choline-deficient-diet (MCD) or normal chow. Liver histology, RT-PCR, hepatic hydroxyproline content, triglycerides and cholesterol levels, and fasting glucose levels assessed hepatic steatosis, inflammation and fibrosis. Further, portal pressure was measured invasively, and kidney pathology was assessed by histology. ApoE−/− mice receiving WD showed abnormal glucose tolerance, hepatomegaly, weight gain and full spectrum of NASH including hepatic steatosis, fibrosis and inflammation, with no sign of renal damage. MCD-animals showed less severe liver fibrosis, but detectable renal pathological changes, besides weight loss and unchanged glucose tolerance. This study describes a murine NASH model with distinct hepatic steatosis, inflammation and fibrosis, without renal pathology. ApoE−/− mice receiving WD represent a novel and fast model with all characteristic features of NASH and MS well suitable for NASH research.
Non-alcoholic fatty liver disease (NAFLD) covers a wide spectrum of diseases ranging from mere steatosis to non-alcoholic stetatohepatitis (NASH) with possible progression to cirrhosis1. NAFLD is characterised by the metabolic syndrome, dyslipidemia, insulin resistance and obesity2,3, and associated with increased liver-related mortality4. The pathogenesis of NAFLD is poorly understood. Besides the “two-hit”-model which states that after the first damage (steatosis), further damage, such as oxidative stress and subsequent inflammation, leads to NASH5, several additional hypotheses on initiation and 1
Department of Internal Medicine I, University of Bonn, Germany. 2Department of Internal Medicine II, University of Bonn, Germany. 3Institute of Pathology, University of Bonn, Germany. 4Department of Internal Medicine III, RWTH University of Aachen, Germany. 5Division of Nephrology, RWTH University of Aachen, Germany. 6Institute of Pathology, RWTH University of Aachen, Germany. 7Department of Human Biology, University of Maastricht, Netherlands. 8Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Germany. *These authors contributed equally to this work. Correspondence and requests for materials should be addressed to J.T. (email: [email protected]) Scientific Reports | 5:12931 | DOI: 10.1038/srep12931
1
www.nature.com/scientificreports/
Figure 1. Study design and general characteristics. (A) Schematic overview of the study design. wt and ApoE−/− mice were fed either with normal chow, high-fat Western diet (WD) rich in cholesterol or methionine and choline deficient diet (MCD) for seven weeks. (B) Body weight of animals before they were sacrificed. ApoE−/− mice fed with WD showed a significant increase in body weight, while mice fed with MCD diet showed a decrease in body weight. (C) Relative liver weight (in % of body weight) in ApoE−/− mice fed with WD was increased, suggesting hepatomegaly, whereas it was not altered in mice fed with MCD diet. Graphs are expressed as means ± standard deviation. p
