Regulation of gut microbiota and intestinal metabolites by Poria cocos oligosaccharides improves glycolipid metabolism disturbance in high-fat diet-fed mice

In this study, we aimed to explore the effect of Poria cocos oligosaccharides (PCO) on glucolipid metabolism disorder. Based on a high-fat diet (HFD)-induced obese mouse model, we demonstrated that PCO ameliorated glucose intolerance and insulin resistance, decreased the levels of blood glucose (187.8±19.8 mg/dL) and insulin (566.3±53.34 ng/L) in HFD-fed mice compared to the Ctrl group (140.4±7.942 mg/dL for glucose, 423.2±19.56 ng/L for insulin). Moreover, PCO treatment suppressed the mRNA expressions of fatty acid synthesis regulators (decreases of 68.8%, 62.8%, and 32.0% for G6Pase, FASN, and DGAT, respectively, vs. HFD group) and pro-inflammatory cytokines in epididymal fat (decreases of 71.9%, 81.5%, 76.0%, 29.3%, and 63.9% for TNF-α, IL-1β, IL-6, COX-5b, and MCP-1, respectively, vs. HFD group). Also, PCO treatment alleviated damage to the intestinal barrier of HFD-fed mice. By 16S rDNA gene sequencing, PCO partly restored the imbalance of gut microbiota in HFD-fed mice, accompanied by the reversal of several intestinal metabolites, including bile acids (BAs), short-chain fatty acids (SCFAs), and tryptophan metabolites. By Spearman's correlation analysis, we found that the changed gut microbiota and their metabolites were significantly correlated with the alteration of metabolic markers. Finally, the significance of gut microbiota in PCO-mediated improvement on glucolipid metabolism disorder was confirmed by an antibiotic depletion experiment and fecal microbiota transplantation. In summary, PCO may be used as a novel prebiotic in the treatment of glucolipid disorders by reshaping intestinal bacteria structure. Our studies also point towards the potential of Poria cocos as a healthy food in the clinical application to metabolic diseases in the future.