A high-fat diet (HFD) causes hyperlipidemia, which worsens disturbances in bile acid (BA) metabolism and gut microbiota. This study aimed to investigate the regulation of flavonoids from whole-grain oat (FO) on BA metabolism and gut microbiota in HFD-induced hyperlipidemic mice. The experiment results showed that FO improved serum lipid profiles and decreased body weight and lipid deposition in HFD-fed mice. Through real-time qualitative polymerase chain reaction (RT-qPCR) and Western blot assays, by up-regulating the expression of PPARα, CPT-1, CYP7A1, FXR, TGR5, NTCP, and BSTP, and down-regulating those of SREBP-1c, FAS, and ASBT, FO suppressed lipogenesis, promoted lipolysis and BA synthesis, and efflux to faeces via the FXR pathway. 16s rRNA sequencing revealed that FO significantly increased Akkermansia and significantly decreased Lachnoclostridium, Blautia, Colidextribacter, and Desulfovibrio. Spearman’s correlation analysis showed that these bacteria were strongly correlated with hyperlipidemia-related parameters. Therefore, our results indicated that FO possessed an antihyperlipidemic effect via regulating the gut–liver axis, i.e., BA metabolism and gut microbiota.
Fucosylated chondroitin sulfate from Pearsonothuria graeffei (FCS- Pg ), a natural macromolecular polysaccharide, has been proven to prevent obesity, but its underlying molecular mechanism is still unclear. C57BL/6 J mice fed on high fat diet (HFD) were administered FCS- Pg lasting for ten weeks. The results demonstrated that FCS- Pg supplementation reduced body weight with dosage manner compared with HFD group. The expressions of intestinal lipid synthesis related proteins such as cluster of differentiation 36 (CD36) in FCS- Pg group were lower than those in the HFD group. Compared with the normal group, HFD caused gut microbiota disorder in the colon. FCS- Pg supplementation at high dosage restored the gut microbiota composition with higher abundance of Alistipes and Bacteroidetes and lower abundance of Colidextribacter , Bilophila and Firmicutes compared with HFD group. Moreover, FCS- Pg decreased the expression of proteins involved in triglyceride synthesis such as glycerol 3-phosphate dehydrogenase 1 (GPD1) and increased the expression of proteins involved in lipolysis and thermogenesis such as adipose triglyceride lipase (ATGL) and uncoupling protein 1 (UCP1) in the white adipose tissue (WAT) compared with HFD group. In conclusion, our study suggested that FCS- Pg significantly prevented obesity and improved WAT function in HFD-fed mice by regulating intestinal lipid metabolism and microflora composition.
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