Chinese Herbal Formulas Si-Wu-Tang and Er-Miao-San Synergistically Ameliorated Hyperuricemia and Renal Impairment in Rats Induced by Adenine and Potassium Oxonate.

BACKGROUND/AIMS Hyperuricemia is an independent risk factor for chronic kidney disease and cardiovascular disease. Here, we examined the combined protective effects of Chinese herbal formula Si-Wu-Tang and Er-Miao-San on hyperuricemia and renal impairment in rats. METHODS Rats were randomly divided into normal rats, hyperuricemic rats, and hyperuricemic rats orally administrated with benzbromarone (4.5 mg·kg⁻¹·d⁻¹), Si-Wu-Tang (3.78 g·kg⁻¹·d⁻¹) and Si-Wu-Tang plus Er-Miao-San (6.48 g·kg⁻¹·d⁻¹) for 4 weeks. Hyperuricemic rats were orally gavaged with adenine (0.1 g·kg⁻¹·d⁻¹) and potassium oxonate (1.5 g·kg⁻¹·d⁻¹) daily for 4 weeks. Serum uric acid, creatinine, total cholesterol (TCH), triglyceride and blood urea nitrogen (BUN) concentrations, as well as urinary uric acid and microalbuminuria were measured weekly. Serum xanthine oxidase (XOD) activity and renal histopathology were also evaluated. The renal expression of organic anion transporter 1 (OAT1) and organic anion transporter 3 (OAT3) was detected by western blot. RESULTS Si-Wu-Tang plus Er-Miao-San lowered serum uric acid, creatinine, triglyceride and BUN levels to a greater degree than did Si-Wu-Tang alone. Si-Wu-Tang plus Er-Miao-San ameliorated microalbuminuria and renal histopathology, as well as decreased serum TCH concentration and XOD activity in hyperuricemic rats. Combination of Si-Wu-Tang and Er-Miao-San also led to a greater increase in OAT1 and OAT3 expression than did Siwutang alone. CONCLUSION Si-Wu-Tang and Er-Miao-San synergistically ameliorated hyperuricemia and renal impairment in rats through upregulation of OAT1 and OAT3.