萆薢总皂苷对大鼠慢性高尿酸血症和肾小管尿酸转运体1表达的影响

目的: 研究萆薢总皂苷对大鼠慢性高尿酸血症的防治作用及对肾脏尿酸转运体1(urate transporter 1,URAT1)表达的影响。 方法: 90只雄性SD大鼠随机分为正常组、模型组、萆薢总皂苷(total saponin of Dioscorea,TSD)高、中、低剂量组(300,100,30 mg·kg^-1)、苯溴马隆(10 mg·kg^-1)组。以氧嗪酸钾联合乙胺丁醇复制大鼠慢性高尿酸血症模型,第3周开始灌胃给药,每天1次,连续4周,测定血尿酸、尿尿酸、尿酸排泄量、黄嘌呤氧化酶(XOD)活性;RT-PCR法、免疫组化法分别测定大鼠肾小管细胞URAT1 mRNA和URAT1蛋白的表达。 结果: 模型组大鼠血尿酸水平显著升高,尿尿酸排泄减少,肾脏URAT1 mRNA和URAT1蛋白高表达。TSD能剂量依赖性地降低高尿酸血症大鼠的血清尿酸水平,增加尿尿酸浓度和尿酸排泄量,降低肾脏URAT1 mRNA和URAT1蛋白的高表达,其作用与苯溴马隆相近;对高尿酸血症大鼠XOD、尿量无明显影响。 结论: TSD有明显的抗高尿酸血症作用,可能是通过抑制大鼠肾脏URAT1的高表达而减少尿酸的重吸收。

Effect of total saponin of Dioscorea on chronic hyperuricemia and expression of URAT1 in rats

Objective: To 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. Method: Ninety male rats were randomly divided into 6 groups: the normal group, the model group, TSD high-, medium- and low-dose (300, 100, 30 mg·kg^-1) groups and the benzbromarone (10 mg·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. Result: Serum 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. Conclusion: TSD has an obvious effect of anti-hyperuricemia. It may reduce the reabsorption of uric acid by inhibiting the high expression of rat renal URAT1.