Uric Acid Distribution In Tissues And Its Solubility In Tissue Fluid

Objectives:The aims of this study were to investigate uric acid distribution in different tissues and organs of normal adult male SD rats,and to explore uric acid solubility in tissue fluid,in order to provide a systematic experimental foundation for dtudying gout and hyperuricemia.Methods:1.Investigation of uric acid distribution in different tissues:1)the tissues of normal adult SD male rats were obtained and homogenized,uric acid in them was determined by phosphotungstic acid agents,and proetin in them was determined with bicinchoninic acid(BCA)reagent.2)Gene expression of xanthine dehydrogenase(Xdh)and urate oxidase(Uox)in tissues at mRNA level was assayed by the second generation high-throughput sequencing technology.3)Expression of Xdh and Uox at protein level was assayed by Western Blot.3)Localization of Xdh and Uox in them was assayed by routine immunohistochemistry(ICH)and immunofluorescence(IF)techniques.2.Uric acid solubility in tissue fulid:1)Macromolecules and micromolecules in serum,plasma and red blood cell lysate were obtained with fiber filters,and uric acid solubility in the tissue fluid rich in or free of macromolecules was determined by phosphotungstic acid agents.2)The macromolecular mechanism of solubilization on uric acid was simulated by seum albumin,sodium lauryl sulfate(an anionic surfactant),polysorbate 80(a nonionic surfactant)and benzalkonium bromide(a cationic surfactant).3)The micromolecular mechanism of solubilization on uric acid was simulated by sodium bicarbonate,sodium carbonate,and phosphates.4)The pH on the solubilization of uric acid was also investigated.Results:1.The organ contained the highest level of uric acid(1592.92?g/mg protein)was adrenal gland in adult SD male rats,followed by duodenum(1122.0436?g/mg protein),liver(483.4497?g/mg protein)and ileum(283.2420?g/mg protein).The serum content was the lowest(11.5396?g/mL).Uric acid mainly distributed in the digestive system,and the level of uric acid in intestinal tissue gradually decreased.The level of uric acid in tissues was positively correlated to the expression level of Xdh,but not to Uox expression.2.Serum and red blood intracelullar fluid were good solvents for uric acid,and their soblubility was 1.4125mg/mL and 0.9425 mg/mL,respectively.The effect of serum in solubilizing uric acid was mainly attributed to small molecular substances.Serum protein contributed a weak effect on uric acid solubility.Alkaline small molecular substances played a major role in uric acid dissolution.Conclusions:Uric acid is mainly disturbuted in the digestive system.Tissue fluid was a good solvent for uric acid,and the main effect is resulted from small molecules.