关键词: 铁观音茶水提物, 高尿酸血症, 有机阴离子转运体, 黄嘌呤氧化酶

Abstract: In recent years, hyperuricemia (HUA) occurs frequently in the population, with strong harmfulness and many complications. In order to explore whether semi-fermented  Tieguanyin tea, a common daily drink, has an auxiliary effect on alleviating HUA, mice were taken as experimental objects, and mice hyperuricemia models were established by the combined method of potassium oxazinate and hypoxanthine. Twenty-one model mice were randomly divided into model group, Tieguanyin tea aqueous extract group, positive drug group, and 7 non-model mice as controls. After 2 weeks of different treatments, mice serum, kidney, liver and small intestine were taken. The pathological changes of various organs were observed, so as to identify the effects of Tieguanyin tea aqueous extract on various organs of hyperuricemia mice from the cellular level. Biochemical indicators with high correlation with HUA were measured: concentration of serum uric acid (UA) and activity of xanthine oxidase (XOD) in liver to determine whether the model was successfully established and whether Tieguanyin tea aqueous extract had a mitigating effect on HUA. qRT-PCR was used to detect the mRNA expression level of genes related to uric acid synthesis and excretion, and Western blot was used to detect the expression level of liver XOD protein, so as to clarify the influence of Tieguanyin tea aqueous extract on HUA from the molecular level. Pathological sections showed that compared with the positive drug group, the mice in Tieguanyin tea aqueous extract group had less kidney and liver damage. Biochemical indexes showed that Tieguanyin tea aqueous extract could reduce serum uric acid level and inhibit XOD activity. From the molecular level, it could be seen that Tieguanyin tea aqueous extract significantly increased the mRNA expression levels of uric acid transporter 1 (URAT1) and organic anion transporter 3 (OAT3) (P<0.05), and the expression of glucose transporter 9 (GLUT9) and organic anion transporter 1 (OAT1) was significantly reduced (P<0.05). Although qRT-PCR and Western blot indicated that the expression level of XOD mRNA and protein increased, but the production of uric acid decreased, suggesting that a certain component in Tieguanyin tea aqueous extract may increase the expression of XOD protein without catalytic activity, thus causing a positive feedback to the transcription and expression of XOD gene. The research indicated that Tieguanyin tea aqueous extract had an alleviating effect on hyperuricemia in mice, and its alleviating effect was related to inhibiting XOD activity, intervening uric acid production process and stimulating or inhibiting mRNA expression of related anion transporters.

Key words: Tieguanyin tea aqueous extract, hyperuricemia, organic anion transporter, xanthine oxidase