Effect of acupuncture stimulation of "Shenshu"(BL23)-"Taixi"(KI3)on levels of serum uric acid and renal URAT1 and OAT1 protein expression in hyperuricemia rats

Abstract

To observe the effect of acupuncture at "Shenshu"(BL23)-"Taixi"(KI3)on the levels of serum uric acid (SUA) and expression of renal urate-anion transporter 1 (URAT1) and organic anion transporter 1 (OAT1) proteins in hyperuricemia (HUA) rats, so as to explore its underlying mechanisms in improving HUA. A total of 25 male Wistar rats were divided into 4 groups: control (n＝6), HUA model (n＝7), BL23-KI3 (n＝6) and Ganshu (BL18)-Taichong (LR3, BL18-LR3 in short, n＝6). The HUA model was established by gavage of Oteracil Potassium (2 g/kg), once daily for 10 days, then once every other day. For rats of the BL23-KI3 group, BL23 and KI3 were stimulated with filiform needles which were rotated for 10 s at a frequency about 100 r/min, and for rats of the BL18-LR3 group, BL18 and LR3 were stimulated with the same methods to those of the BL23-KI3 group. The treatment of both acupuncture groups was conducted once daily, 6 times a week (except Sundays) for 3 weeks. The contents of SUA and serum creatinine (SCr) were assayed by using an automatic biochemical analyzer. The pathological changes of the right kidney tissue were observed under light microscope after hematoxylin eosin (H.E.) staining, the immunoactivity of URAT1 and OAT1 of the right kidney tissue was determined by immunohistochemistry, and the expression of URAT1 and OAT1 proteins of the left kidney tissue detected by Western blot (WB). After modeling, the content of SUA and the expression of renal URAT1 protein (shown by both immunoactivity and WB) were significantly increased (P<0.01), but that of renal OAT1 protein was obviously decreased in the model group compared with the control group (P<0.01). There was no notably change in the level of SCr in the model group relevant to the control group (P>0.05). Following acupuncture intervention, the SUA content and URAT1 expression in both BL18-LR3 and BL23-KI3 groups were considerably down-regulated (P<0.05, P<0.01), and the expression of OAT1 protein in the BL23-KI3 group (not the BL18-LR3 group) were obviously up-regulated relevant to the model group (P<0.01). The effects of BL23-KI3 were significant superior to those of BL18-LR3 in down-regulating the expression of URAT1 and up-regulating OAT1 protein (P<0.01, P<0.05). Acupuncture of "BL23" and "KI3" can effectively down-regulate SUA level in HUA rats, which may be related to its effects in down-regulating the expression of URAT1 and up-regulating the expression of OAT1 in the kidney tissue.