Effect of multiple binge alcohol on diet-induced liver injury in a mouse model of obesity

Abstract

Background:Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are highly prevalent liver diseases that may coexist and contribute significantly to liver disease-related mortality. Obesity is a common underlying risk factor for both disorders. There has been little research investigating the combined effects of high fat diet (HFD) and alcohol. Current mouse models of alcohol- or fat-rich diet alone do not lead to severe liver injury. There is a need to develop animal models recapitulating human settings of drinking and diet to study the mechanisms of liver injury progression.Methods:C57BL6 male mice were fed either chow or HFD ad libitum for 12 weeks. A sub-set of mice from each group were also given alcohol (2 g kg−1 body weight) twice a week via intra-gastric lavage. Animals were monitored progressively for weight gain and blood and livers were harvested at termination. The extent of liver injury was examined by histopathology as well as by liver and serum biochemistry. The expression of lipid metabolism, inflammation and fibrogenesis-related molecules was examined by quantitative reverse transcription PCR (Q-PCR) and immunofluorescence staining.Results:HFD significantly increased total body weight, triglyceride and cholesterol, whereas alcohol increased liver weight. Alcohol+HFD in combination produced maximum hepatic steatosis, increased micro- and macro-vesicular lipid droplets, increased de novo lipogenesis (steroid response-element binding protein 1 (SREBP-1) and stearoyl-CoA desaturase-1 (SCD-1)) and proliferation peroxisome activated receptor alpha (PPARα), and decreased fatty acid β-oxidation (Acyl-CoA oxidase 1 (ACOX1)). Alcohol+HFD treatment also increased the inflammation (CD45+, CD68+, F4/80+ cells; tumour necrosis factor-alpha (TNF-α), F4/80 mRNAs) and fibrogenesis (vimentin+ activated stellate cells, collagen 1 (Col1) production, transforming growth factor-beta (TGF-β) and Col-1 mRNAs) in mice livers.Conclusions:We report a novel mouse model with more severe liver injury than either alcohol or HFD alone recapitulating the human setting of intermittent alcohol drinking and HFD.

Interaction Between Alcohol Use and Metabolic Risk Factors for Liver Disease: A Critical Review of Epidemiological Studies

“…The synergistic interactions observed in these epidemiological studies are well in line with mechanistic studies showing hepatotoxic effects from the combined exposure to alcohol and high‐fat diet above and beyond the sum of their individual effects (Duly et al, ; Minato et al, ; Xu et al, ).…”

“…It could be speculated that a liver affected by steatosis may lack the capacity of a normal liver to recover after each episode of drinking during the break from alcohol intake. In support of this, animal studies show that intermittent alcohol administration serves as a “second hit” by aggravating hepatic oxidative stress and promoting steatohepatitis and fibrosis in mice with obesity‐induced steatosis (Duly et al, ; Minato et al, ).…”

“…There is a considerable overlap in the molecular pathways between alcoholic and nonalcoholic liver disease, and the diseases share genetic risk factors and histological features in common. Animal studies have suggested synergism between the hepatotoxic effects of alcohol and high‐fat diet–induced obesity (Duly et al, ; Minato et al, ; Xu et al, ).…”

Hepatic Peroxisome Proliferator-Activated Receptor Gamma Signaling Contributes to Alcohol-Induced Hepatic Steatosis and Inflammation in Mice

“…MCP1, IP‐10, and KC have been shown to play a role in hepatic inflammation or injury (Mandrekar et al., ; Reiberger et al., ; Sermon et al., ). Our and other groups have shown that alcohol feeding induces MCP1, IP‐10, KC, Ly6G, and F4/80 (Duly et al., ; Sun et al., ; Zhong et al., ). However, the underlining mechanisms remain unclear.…”

The TIR/BB‐loop mimetic AS‐1 prevents non‐alcoholic steatohepatitis and hepatic insulin resistance by inhibiting NLRP3‐ASC inflammasome activation

“…Standard immunohistochemical analysis with citrate antigen retrieval was performed to localize 3‐nitrotyrosine (3‐NT) expression as previously described (Dixon et al , ). Standard immunofluorescence analysis was performed to localize F4/80, CD68 expression as previously described (Zhang et al , ; Duly et al , ). Haematoxylin–eosin‐stained paraffin‐embedded and Oil Red O stained frozen liver tissues isolated from mice were graded for hepatic steatosis and inflammation as described previously (Yamaguchi et al , ).…”