Oleanolic Acid Alleviates Hyperuricemia via Gut Microbiota Control the Integrity of Gut Barrier and the Expressions of Urate Transporter in Mice

Hyperuricemia (HUA) is a globally prevalent metabolic disorder characterized by an imbalance in uric acid (UA) production and excretion. In this study, we found that oleanolic acid (OA), a natural pentacyclic triterpene, effectively reduced HUA and associated kidney injury in C57BL/6J mice. A 12-week OA treatment significantly and dose-dependently reduced UA and creatinine levels in serum and urine while suppressing hepatic xanthine oxidase activity in HUA mice. Mechanistic analysis revealed that OA modulates the expression of urate transporters including ABCG2, GLUT9, and URAT1 in the kidney and small intestine. Furthermore, OA restored gut microbiota imbalances, increased short-chain fatty acid production, and enhanced the expressions of intestinal tight junction proteins in HUA mice, thereby improving gut barrier integrity in HUA mice. Consequently, fecal microbiota transplantation (FMT) was employed to illustrate the major mediating role of gut microbiota in OA's alleviation of HUA in mice. Recipient HUA mice transplanted with feces from OA-treated HUA mice exhibited significantly lower blood and urinary UA levels, reduced kidney inflammation, and improved gut microbiota balance compared to those receiving feces from untreated HUA mice (p < 0.05). Additionally, FMT normalized urate transporter expression and reinforced intestinal tight junctions in recipient mice. These findings underscore that OA mitigates HUA primarily by modulating gut microbiota, regulating urate transporter expression, and reinforcing gut barrier integrity, offering novel insights into its preventive potential for managing HUA and related complications.