Morin Improves Urate Excretion and Kidney Function through Regulation of Renal Organic Ion Transporters in Hyperuricemic Mice

Abstract

Purpose. Morin (3,5,7,2′,4′-pentahydroxyflavone), a plant-derived flavonoid, has beneficial effects in animals with various diseases including hyperuricemia and renal dysfunction. Since the decreased renal excretion of uric acid is the hallmark of hyperuricemia and renal dysfunction, here we studied the effects of oral morin administration on renal organic ion transporters in oxonate-induced hyperuricemic mice. Methods. The hyperuricemia in mice was induced by potassium oxonate. Uric acid and creatinine concentrations in urine and serum, and fractional excretion of uric acid (FEUA) were performed to evaluate urate handling. Changes in the expression levels of renal organic ion transporters were detected by Western blotting and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Results. Morin treatment significantly reduced urinary uric acid/creatinine ratio and FEUA, resulting in the reduction of serum uric acid levels in hyperuricemic mice. And kidney dysfunction was also improved after morin treatment in this model. Protein and mRNA levels of renal glucose transporter 9 (mGLUT9) and urate transporter 1 (mURAT1) were significantly decreased, and renal organic anion transporter (mOAT1) levels were remarkably increased in morin-treated hyperuricemic mice. Morin treatment also blocked down-regulation of renal organic cation and carnitine transporters (mOCT1, mOCT2, mOCTN1 and mOCTN2) in hyperuricemic mice. Conclusion. These results suggest that morin exhibits uricosuric effect via suppressing urate reabsorption and promoting urate secretion in the kidney of hyperuricemic mice and may help to attenuate deleterious effects of hyperuricemia with renal dysfunction.