Pharmacodynamic And Acute Toxicity Study Of XOR Inhibitor WN1703 In Hyperuricemia Model Rats

Hyperuricemia is a disease caused by disorder of purine metabolism or decreased uric acid excretion in the body,which results in the blood uric acid level above the normal range.Xanthine oxidoreductase（XOR）,a key enzyme in the purine metabolism,catalyzes the production of uric acid from hypoxanthine and xanthine.Therefore,inhibition of XOR can effectively reduce blood uric acid levels to achieve the purpose of prevention and treatment of hyperuricemia.Appropriate animal model is the basis for the study on drug activity.The establishment of an animal model of hyperuricemia is of great significance for the study and search of drugs to treat hyperuricemia.Based on our previous research,WN1703 were screened out with significant XOR inhibition in vitro and uric acid lowering activity on the mouse model of acute hyperuricemia and long-term hyperuricemia.In this paper,pharmacodynamic and acute toxicity studies were carry out with WN1703.The following main work of this thesis:1)Establishment and study of a hyperuricemia rat model.The results show that oral administration of potassium oxonate at a dose of 750 mg/kg,combined with yeast extract food,can establish a continuous and stable rat chronic hyperuricemia accompanied by secondary cardiovascular disease.2)Application of long-term hyperuricemia rat model.The rats were divided into control group,model group,febuxostat-treated group（5 mg/kg）,low-dose group of WN1703（2.5mg/kg）,middle-dose group of WN1703（5 mg/kg）and high-dose group of WN1703（10mg/kg）.The hyperuricemia model was establish by potassium oxonate at a dose of 750 mg/kg,combined with yeast extract food into SPF male SD rats.The level of the serum levels of uric acid（UA）,blood urea nitrogen（BUN）,creatinine（Cr）,insulin（INS）,blood glucose（GLU）,triglyceride（TG）,cholesterol（CHOL）,low density lipoprotein chesterol（LDL-C）,high density lipoprotein chesterol（HDL-C）,antioxidant factor,inflammatory factor together with H&E,immunohistochemistry staining of kidney,liver and heart were measured to evaluate the pharmacodynamic of WN1703.The result is as follows:1.The serum UA levels of the febuxostat-treated group,low-dose group of WN1703,medium-dose group of WN1703,and the high-dose group of WN1703 were significantly lower than that of the model group（P<0.001）.The serum UA levels of the high-dose group of WN1703 were equivalent with the control group（P>0.05）.2.The serum Cr and BUN levels of model group had an increasing trend,suggesting that a slight renal injury,while the three dose-administered groups of WN1703 and febuxostat-treated group showed a downward trend（P>0.05）.3.Blood lipid disorders in model group rats accompanied by increased TG（P<0.001）,CHOL（P<0.01）,and LDL-C（P<0.001）.The TG,LDL-C levels of the febuxostat-treated group were lower than that of the model group（P<0.01）,while the three dose groups of WN1703 can significantly reduce serum TG,CHOL and LDL-C.Medium-dose group（P<0.01）and high-dose group（P<0.001）of WN1703 had the most significant effect on relieving blood lipid disorders.4.WN1703 can also improve the antioxidant capacity of rats.The medium-dose group and high dose group of WN1703 can increase the activity of superoxide dismutase（SOD）and glutathione peroxidase from bovine erythrocytes（GSH-PX）,and reduce the activity of malondialdehyde（MDA）,while febuxostat can only increase serum SOD activity,therefore WN1703 had better antioxidant capacity than febuxostat.5.Compared with the control group,the level of xanthine oxidase（XO）and adenosine deaminase（ADA）in serum and liver homogenate of model group rat were increased（P<0.05）.WN1703 and febuxostat significantly inhibited the activities of XO and ADA（P<0.05）.6.The level of serum monocyte chemotactic protein-1（MCP-1）（P<0.001）,tumor necrosis factor-α（TNF-α）（P<0.001）and interleukin-1β（IL-1β）（P<0.01）in the model group rats were significantly increased.The three dose groups of WN1703（P<0.01）and febuxostat-treated group（P<0.001）can reduce serum MCP-1 activity,high-dose group of WN1703 can also reduce the serum IL-1βlevel（P<0.05）,while WN1703 had no effect on TNF-α.7.According to the pathological results of kidney,liver and hear,hyperuricemia will cause certain damage to the liver and kidney.Febuxostat and WN1703 can alleviate liver and kidney damage caused by hyperuricemia.The effect of treating liver and kidney injury was a dose-dependent manner.3)Acute toxicity study of WN1703.Acute toxicity study of WN1703 was done in 80SPF rats（male and female in half）.The results showed that the LD₅₀of WN1703 in rats was1493.96 mg/kg upon oral administration,the 95%confidence interval calculation was1349.13-1654.34 mg/kg,indicating WN1703 could be classified as practically low-toxic compound according to WHO.The target organs of WN1703 were liver and kidney.In summary,WN1703 is a low-toxic compound with the significant uric acid-lowering effect,which can partially alleviate liver and kidney damage and oxidative stress caused by hyperuricemia.More systematic pharmaceutical studies can be carried out later.