OBJECTIVETo study the preventive and therapeutic effects of total saponin of Dioscorea (TSD) on chronic hyperuricemia, and its effect on urate transporter 1 (URAT1) in rats.

METHODNinety male rats were randomly divided into 6 groups: the normal group, the model group, TSD high-, medium- and low-dose (300, 100, 30 mg x kg(-1)) groups and the benzbromarone (10 mg x kg(-1)) group. Potassium oxonate and ethambutol were adopted to establish the chronic hyperuricemia model Since the third week, all the rats were intragastrically administered with drugs for 4 weeks, once a day, in order to determine their uric acid in serum and urine, uric acid excretion and xanthine oxidase (XOD). URAT1 mRNA and URAT1 protein expression in rat renal tubular cells were determined by RT-PCR and immunohistochemistry method respectively.

RESULTSerum uric acid level of the model group increased significantly, while uric acid excretion decreased, with high expressions of renal URAT1 mRNA and URAT1 protein. TSD could dose-dependently reduce the serum uric acid level of chronic hyperuricemia rats, increase the concentration of uric acid and uric acid excretion in urine, and reduce renal URAT1 mRNA and URAT1 protein expression. Its effects were similar with that of benzbromarone, but with no significant effect on XOD and urinary volume of chronic hyperuricemia rats.

CONCLUSIONTSD has an obvious effect of anti-hyperuricemia It may reduce the reabsorption of uric acid by inhibiting the high expression of rat renal URAT1.