Objective To explore whether bifidobacteria attenuates high-fat diet-induced non-alcoholic fatty liver disease (NAFLD) in C57BL/6 mice by altering the gut microbiota, reducing local intestinal inflammation, and modulating systemic inflammation.

Methods 32 male C57BL/6 mice were randomly allocated into four groups: common feed group, common feed group with bifidobacteria, high fat diet group, high fat diet group with bifidobacteria, each group is divided into 2 cages, 4 for each cage. Serum glucose and lipid metabolism and liver function levels in mice were detected. Mouse liver steatosis was assessed by Oil red O staining and hematoxylin-eosin (H-E) staining. Expression of TNF-α, IL-6, ZO-1 and occludin in mouse ileum and colon tissue by real time PCR.Gut microbiota profiles were established through 16SrRNA amplicon sequencing.

Results The degree of liver steatosis in C57BL/6 mice in the bifidobacteria intervention group was significantly lower than that in the high-fat diet-fed group. The expression of inflammatory factors TNF-α and IL-6 in the bifidobacteria intervention group was significantly decreased. The species abundance and diversity of gut microbiota was decreased in NAFLD group. The results of PcoA and NMDS showed that there were significant differences in the composition of the flora among the groups. The gut microbial structure was changed, and abundance of Firmicutes was increased significantly after treated with bifidobacteria.

Conclusion Taken together, these data suggest that bifidobacteria has a protective effect on NAFLD via changing the components of gut microbiota.