1, 2 Fatty liver is the earliest response to alcohol drinking and FDA-approved Drug Library ic50 occurs in almost everyone who drinks heavily,3 whereas more severe forms of alcoholic liver injury typically develop in up to 35% of heavy drinkers.1, 2 No specific medical treatment is needed for patients with simple alcoholic
fatty liver, which usually resolves within several weeks of alcohol withdrawal. More severe forms of alcoholic liver disease such as alcoholic hepatitis require treatment. Current therapeutic options for alcoholic hepatitis include corticosteroids or tumor necrosis factor alpha (TNF-α) inhibitor therapy; however, these treatments have generated controversial results and are associated with increased rates of infection.2, 4-7 Interleukin-22 (IL-22), a recently identified cytokine that is produced by Th17 cells and natural killer cells, has been shown to play an important role in controlling bacterial infection, homeostasis, and tissue repair.8, 9 The biological effect of IL-22 was believed to be mediated mainly via activation of the signal transducer and activator of transcription 3 (STAT3) signaling pathway through
binding of IL-22 receptor 1 (IL-22R1) and IL-10R2, although high concentrations of IL-22 can also activate many other signaling pathways including STAT1, STAT5, mitogen-activated check details protein kinases, AKT, nuclear factor-κB, activator protein-1, and so forth.8 Recently, we and others have demonstrated that IL-22 treatment prevents T cell hepatitis,10 stimulates liver regeneration,10, 11 and improves fatty liver.12 Thus, we hypothesize that IL-22 treatment could be a potential therapeutic option to ameliorate alcoholic liver disease. Here, we test this hypothesis in a murine model of alcoholic liver injury induced by chronic-binge ethanol feeding. During the last 5 decades,
many animal heptaminol models of alcoholic liver injury have been developed,13-17 which have significantly helped us understand the molecular mechanisms of alcoholic liver disease. Presently, the most commonly used model for alcoholic liver injury in rodents is voluntary feeding with the Lieber-DeCarli liquid ethanol-containing diet.17-22 However, this model only induces minor hepatic lesions such as fatty liver and slight elevation of serum ALT, especially in male mice.17-22 In contrast, the Tsukamoto-French model, which administers a higher dose of ethanol through continuous intragastric feeding, causes more severe forms of liver injury such as steatosis and mild liver inflammation and fibrosis.13, 23 However, this model has not been widely used in many laboratories because of its technical difficulty, requirement for animal husbandry, and the expense of equipment.23 Lastly, another popular animal model of liver injury features ad libitum feeding of a liquid diet containing ethanol followed by a challenge with endotoxin or hepatotoxins, or other substances.