Simiao pill ameliorates urate underexcretion and renal dysfunction in hyperuricemic mice

Simiao pill is one of the most frequently prescription in traditional Chinese medicine to treat gout and hyperuricemia.

We investigated the effects of Simiao pill on urate excretion and renal function and examined whether renal organic ion transporters are involved in potassium oxonate-induced hyperuricemic mice.

Water extract of Simiao pill at 507, 1014 and 2028mg/kg was orally administered to hyperuricemic and normal mice for 7 days, and allopurinol (5mg/kg) was given as a positive control. Serum and urine levels of uric acid and creatinine, and fractional excretion of uric acid (FEUA) were measured in hyperuricemic and normal mice treated with Simiao pill and allopurinol. Simultaneously, the mRNA and protein levels of mouse urate transporter 1 (mURAT1), glucose transporter 9 (mGLUT9) and organic anion transporter 1 (mOAT1) and organic cation/carnitine transporters (mOCT1, mOCT2, mOCTN1 and mOCTN2) in the kidney were analyzed by semi-quantitative RT-PCR and Western blotting methods, respectively.

Simiao pill significantly reduced serum uric acid levels and increased FEUA dose-dependently in hyperuricemic mice. And it effectively reversed oxonate-induced alterations in renal mURAT1, mGLUT9 and mOAT1 mRNA and protein levels, resulting in the enhancement of renal urate excretion in mice. Moreover, Simiao pill decreased serum creatinine levels, as well as increased renal mOCT1, mOCT2, mOCTN1 and mOCTN2 mRNA and protein levels, leading to improve renal dysfunction in this model.

These findings suggest that Simiao pill processes uricosuric and nephroprotective actions by regulating renal organic ion transporters in hyperuricemic animals.