Rice bran oil modifying gut microbiota ameliorates hypercholesterolemia via bile acids in hamsters

Rice bran oil displays cholesterol-lowering features, but the underlying mechanism has not been clarified. Here, we found that rice bran oil changed the gut microbiota composition in hamsters. Fecal microbiota transplantation experiment showed that the anti-hypercholesterolemia function of rice bran oil was associated with suppressing Bifidobacterium abundance, which increased the conjugated bile acids (BAs)/unconjugated BAs ratio in cecum and liver, and the altered ratio could inhibit FXR expression in the intestinal tissues, which caused more cholesterol to reversely transport to liver. Under the action of CYP27A1 enzyme in liver tissue, these cholesterols are catabolized to BAs, which are then promoted to produce conjugated BAs through the action of Sult2a1. Our results explored the anti-hypercholesterolemia mechanism of rice bran oil, and suggest that decreased Bifidobacterium and/or inhibited intestinal FXR may be potential therapies to hypercholesterolemia.