Probiotic Bifidobacterium Lactis V9 attenuates hepatic steatosis and inflammation in rats with non-alcoholic fatty liver disease

Abstract Both steatosis and inflammation are key pathological events in the progression of non-alcoholic fatty liver disease (NAFLD). Probiotics are beneficial in the prevention and treatment of NAFLD. Bifidobacterium animalis subsp.lactis V9 (V9) is a newly isolated strain with favorable probiotic properties. The study aims to evaluate the effects and mechanisms of V9 on the hepatic steatosis and inflammatory responses in a rat model of NAFLD induced by high-fat diets (HFD). Our results showed that administration with V9 significantly attenuated HFD-induced increases in the levels of alanine transaminase (ALT) and aspartate aminotransferase (AST), accompanied by alleviated hepatic steatosis. V9 supplementation decreased the accumulation of hepatic triglyceride (TG) and free fatty acid (FFA), while increasing the levels of glycogen. The levels of serum glucose were also decreased in HFD rats administrated with V9. Meanwhile, the transcription of SREBP-1c and FAS was reduced and the hepatic expression of phosphorylated-AMPK and PPAR-α was restored by V9 administration. V9 suppressed the production of inflammatory cytokines (e.g. IL-6, IL-1β, and TNF-α) in HFD-fed rats. The anti-inflammatory effect of V9 was found to be associated with the inhibition of hepatic expression of TLR4, TLR9, NLRP3, and ASC mRNA. Furthermore, the activation of ERK, JNK, AKT and NF-κB was suppressed by V9 treatment. These results indicated that Bifidobacterium Lactis V9 improved NAFLD by regulating de novo lipid synthesis and suppressing inflammation through AMPK and TLR-NF-κB pathways, respectively.