Lactobacillus extracellular vesicles alleviate alcohol-induced liver injury in mice by regulating gut microbiota and activating the Nrf-2 signaling pathway.

Lactobacillus derived extracellular vesicles (LAB-EVs) are nanosized particles secreted from Lactobacillus during fermentation, and therefore exist universally in fermented foods such as yogurt, pickles, and fermented beverages. In this study, three LAB-EVs were prepared using a simple scalable method, and then their structures, compositions, and biosafety properties were characterized. The protective properties and potential mechanisms of action of the LAB-EVs against alcoholic liver disease were studied. All three LAB-EVs alleviated alcohol-induced liver injury. It was shown by reduction of liver index, histological damage, liver function impairment, inflammation, and liver oxidative status. The results showed that three LAB-EVs positively promoted the diversity of intestinal flora in mice. Additionally, the relative hepatic protein level of Nrf-2, HO-1, and CYP2E1 was also regulated by LAB-EVs. In summary, these facts suggest that the three LAB-EVs can alleviate alcohol-induced liver damage, by positively modulating the intestinal flora and activation of the Nrf-2 signaling pathway. These results may facilitate the understanding of the composition and function of Lactobacillus fermented food and also the development of Lactobacillus fermented functional food.