Lactobacillus acidophilus YL01 and its exopolysaccharides ameliorate obesity and insulin resistance in obese mice via modulating intestinal specific bacterial groups and AMPK/ACC signaling pathway.

Probiotics intervention by Lactobacillus acidophilus has potential effect on alleviating obesity and insulin resistance. However, the limited knowledge of functional substances and potential regulatory mechanisms hinder their widespread application. Herein, L. acidophilus YL01 was firstly isolated from Chinese traditional yogurt, demonstrating inhibitory activities on amylase and glucosidase that are comparable to those of L. rhamnosus LGG. Besides, the oral administration of L. acidophilus YL01 and its EPS significantly reduced body weight in high-fat mice (p < 0.05), as well as fat accumulation in liver and adipocytes. Moreover, they not only reduced fasting blood glucose and glucose/insulin resistance, but also improved dyslipidemia, liver function and inflammation. Further high-performance liquid chromatography analysis and Fourier transform infrared spectroscopy indicated that EPS is an acidic polysaccharide, characterized by a molecular weight of 952 kDa and predominantly composed of glucose. Additionally, the mechanism investigation revealed that the L. acidophilus YL01 and EPS demonstrated limited efficacy in restoring the composition of gut microbiota, but rather exerted an influence on the abundance of specific bacterial groups. The enrichment of the bacterial groups resulted in the increase of acetic acid and butyric acid, which further mediates the gut-liver crosstalk in regulating lipid metabolism by the activation of AMPK/ACC pathway.