Abstract
Aflatoxin B1 (AFB1) is a widespread contaminant in foods and feedstuffs, and its target organ is the liver. Melatonin (MT) has been shown to alleviate inflammation in organs and remodel gut microbiota in animals and humans. However, the underlying mechanism by which MT alleviates AFB1-induced liver injury remains unclear. In the present study, MT pretreatment markedly increased the expression of intestinal tight junction proteins (ZO-1, Occludin, and Claudin-1), decreased intestinal permeability, reduced production of gut-derived LPS and remodeled gut microbiota, ultimately alleviated AFB1-induced liver injury in mice. Interestingly, MT pretreatment failed to exert beneficial effects on the intestine and liver in antibiotic-treated mice. Meanwhile, MT pretreatment significantly increased the FXR protein expression of ileum, and decreased the TLR4/NF-κB signaling pathway related mRNA and proteins (TLR4, MyD88, p-p65 and p-IκBα) expression in livers of AFB1-exposed mice. Subsequently, pretreatment by Gly-β-MCA, an intestine-selective FXR inhibitor, blocked the alleviating effect of MT on liver injury through increasing the liver-specific expression of TLR4/NF-κB signaling pathway related mRNA and proteins (TLR4, MyD88, p-p65 and p-IκBα). In conclusion, MT pretreatment ameliorated AFB1-induced liver injury and the potential mechanisms may be related to regulate gut microbiota/intestinal FXR/liver TLR4 signaling axis, which provides strong evidence for the protection of gut-derived liver inflammation. This article is protected by copyright. All rights reserved.
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