Dietary Bacillus subtilis supplementation alleviates alcohol‑induced liver injury by maintaining intestinal integrity and gut microbiota homeostasis in mice

Alcoholic liver disease (ALD) is a worldwide health problem with limited therapeutic options, which is associated with gut-derived endotoxins, particularly lipopolysaccharide (LPS) and intestinal microbiota dysbiosis. Recently, probiotics, synbiotics and other food additive interventions have been shown to be effective in decreasing or preventing the progression of ALD. Bacillus subtilis (B. subtilis) and its metabolic products are widely used as food additives to maintain intestinal health, but the protective effects of B. subtilis against alcohol-induced liver injury are poorly understood. In the present study a chronic alcohol-induced liver injury model was constructed based on the Lieber-DeCarli diet and it aimed to determine whether dietary B. subtilis supplementation may alleviate alcohol-induced liver injury. Results revealed that prophylactic B. subtilis supplementation partially restored gut microbiota homeostasis and relieved alcohol-induced intestinal barrier injury, which significantly decreased the translocation of bacterial endotoxins to the blood. In addition, the decreased serum LPS alleviated hepatic inflammation via the toll-like receptor 4 pathway, resulting in improved hepatic structure and function. These results demonstrated that dietary B. subtilis supplementation imparts novel hepatoprotective functions by improving intestinal permeability and homeostasis.