Chinese Sumac (Rhus chinensis Mill.) Fruits Prevent Hyperuricemia and Uric Acid Nephropathy in Mice Fed a High-Purine Yeast Diet

Hyperuricemia (HUA) is a prevalent chronic disease, characterized by excessive blood uric acid levels, that poses a significant health risk. In this study, the preventive effects and potential mechanisms of ethanol extracts from Chinese sumac (Rhus chinensis Mill.) fruits on HUA and uric acid nephropathy were comprehensively investigated. The results demonstrated a significant reduction in uric acid levels in hyperuricemia mice after treatment with Chinese sumac fruit extract, especially in the high-dose group, where the blood uric acid level decreased by 39.56%. Visual diagrams of the kidneys and hematoxylin and eosin (H&E)-stained sections showed the extract's effectiveness in protecting against kidney damage caused by excessive uric acid. Further investigation into its mechanism revealed that the extract prevents and treats hyperuricemia by decreasing uric acid production, enhancing uric acid excretion, and mitigating the oxidative stress and inflammatory reactions induced by excessive uric acid in the kidneys. Specifically, the extract markedly decreased xanthine oxidase (XOD) levels and expression in the liver, elevated the expression of uric acid transporters ABCG2, and lowered the expression of uric acid reabsorption proteins URAT1 and SLC2A9. Simultaneously, it significantly elevated the levels of endogenous antioxidant enzymes (SOD and GSH) while reducing the level of malondialdehyde (MDA). Furthermore, the expression of uric-acid-related proteins NLRP3, ACS, and Caspase-3 and the levels of IL-1 beta and IL-6 were significantly reduced. The experimental results confirm that Chinese sumac fruit extract can improve HUA and uric acid nephropathy in mice fed a high-purine yeast diet. This finding establishes a theoretical foundation for developing Chinese sumac fruit as a functional food or medicine for preventing and treating HUA.