The effect of anti-imbalance on glycolipid metabolic homeostasis via the liver–gut axis intervened by 3′-sialyllactose in obese mice

Abstract

Sialic acid could ameliorate disorders associated with glycolipid metabolism. 3′-Sialyllactose (3′-SL), a type of oligosaccharide, contains sialic acid. We examined the effects of 3′-SL on glycolipid metabolism in obese mice with high fat diet and explore the underlying mechanisms. A total of 160 male C57BL/6J mice were fed with high-fat diet for 8 weeks to construct obese mice model. Sixty successfully constructed obese mice were randomly divided three 3′-SL dosage-dependent groups, one free sialic acid N-acetylneuraminic acid (Neu5Ac) group, and one blank control group. Each group of obese mice (n = 12) was continuously supplemented by 3′-SL or Neu5Ac for 10 weeks. Ten-week 3′-SL supplementation and Neu5Ac supplementation both yielded remarkedly lower body weight, reduced fat content, increased energy expenditure and active daily exercises with improved glycolipid biomarkers, and attenuated proinflammation. 3′-SL increased the colonic abundances of Akkermansia, Lactobacillus, and Solibacillus and reduced those of Enterobacter and Enterococcus. Changes were also observed in colonic and liver transcript and metabolites, which were mainly enriched in glycolipid metabolism, ameliorated immune function, and mitigated inflammatory signals, autophagy, bile acid metabolism, and insulin resistance. Akkermansia and Solibacillus were significantly associated with changes in colonic metabolites and transcriptome genes. The liver bile component and glucose metabolites were significantly correlated with transcriptional gene expression in the aforementioned differential pathways. Therefore, 3′-SL can enhance the gut microbiota, regulate intestinal immunity and bile acid metabolism, reduce liver oxidative stress and autophagy processes, alleviate chronic inflammation levels, and improve islet function and lower blood sugar levels by acting through the gut–liver axis.