Investigation of the mechanism by which Tegillarca granosa polysaccharide regulates non-alcoholic fatty liver disease in mice by modulating Lactobacillus Johnsonii

Non-alcoholic fatty liver disease (NAFLD), a prevalent chronic liver disease, is marked by excessive lipid deposition in the liver without alcohol abuse. Scapharca subcrenatum, a major Chinese farmed bivalve, yields S. subcrenatum polysaccharide (TGP), an active substance with known biological activity. Previous studies revealed TGP's significant regulatory effect on a high-fat diet (HFD)-induced NAFLD in mice. However, the precise mechanisms, particularly involving gut microbiota, remain unclear. In the current study, an antibiotic-treated mouse model was established to determine the mechanistic role of the gut microbiota in the observed anti-obesity effects of TGP. In addition, 16S rRNA genomic and metagenome-derived taxonomic analyses were performed to assess the gut microbial populations. The results showed that TGP selectively enhanced the number of the eosinophilic bacterium Lactobacillus johnsonii , which was reduced in HFD mice. Of note, the oral administration of L. johnsonii formulations to HFD mice alleviated NAFLD, and this was related to regulating lipid metabolism and the accumulation of lipids in the liver. Therefore, the current study uncovered a potential pathway for developing NAFLD treatment strategies based on the interaction between TGP and the gut microbiota.