RESUMEN
OBJECTIVE Tostudytheeffectofeffectivefractions(EFC)frommodifiedSimiaoWan (MSW)onthelevelofuricacidinhyperuricemicratsandinvestigatethemechanism.METHODS Two types of hyperurice mic models were established.A persistant hyperurice mic model was prepared by giving rats oxonic acid 200 mg·kg -1 and feeding the m with hypoxanthine.The models were ig given with modified Simiaowan (MSW)50 g·kg -1 or EFC 1 2.5,25 and 50 g·kg -1 consecutively for 5 d.The models were treated with MSW or EFC 50 g·kg -1 for 3 d.After the final treatment,the uric acid concen-trations in seru m and urine were determined by an auto matic bioche mistry analyzer.The activity of xan-thine oxidase (XOD )in the serum and liver was determined by enzymic colorimetric method.The activity of purine nucleoside phosphorylase (PNP)and uricase was detected by spectrophotometry. RESULTS Comparedwithnormalcontrolgroup,theserumlevelofuricacidinbothmodelgroupswas remarkably increased(P<0.01 ).Compared to model control group,MSW 50 g·kg -1 and EFC 12.5, 25 and 50 g·kg -1 significantly reduced the serum level of uric acid(P<0.05,P<0.01 ),but increased the activity of erythrocyte PNP(P<0.01 )in the oxonic acid potassium-induced hyperuricemia rats. MSW 50 g·kg -1 and EFC 50 g·kg -1 elevated the activity of liver uricase in the nicotinic acid-induced hyperuricemia rats(P<0.05).EFC 50 g·kg -1 also significantly decreased the serum XOD activity of hyperuricemicrats.CONCLUSION EFCsignificantlyinhibitstheserumlevelofuricacidinhyperurice-mic rats,which might involve down-regulation of protein levels of serum XOD to inhibit the production of uric acid and activation of uricase to pro mote the deco mposition of uric acid.