水产品中嘌呤在贮藏加工中的变化规律及其对尿酸生成的影响

The hypothesis whether excessive intake of purine-rich seafood increases the uric acid production and aggravates gout symptoms has attracted extensive attentions of people about seafood safety. The purpose of this study is to elucidate the relationship between purine in seafood and uric acid production, to provide consumers with scientific diet guide. The contents of purine bases in food were investigated by reversed phase ion-pair chromatography in the former stage. In order to find out the specificity of purine in seafood, all kinds of purine and their precursors will be determined with chemical analysis methods. The key purine which influences uric acid production will be defined by poultry animal model. Research on the metabolism regulations of purine and the key enzymes of purine transformation including adenosine deaminase, guanosine deaminase and xanthine oxidase will be carried out. At the same time, the effect of storage and processing methods on purine and their key enzymes during transformation will be explored. New theory will be established by clarifying the mechanism of purine transformation in seafood and constructing effective methods to reduce uric acid production. These findings can also provide new thoughts and theoretical support for the control of purine in other foods.

过多摄入富含嘌呤的水产品是否会增加尿酸的含量进而加剧痛风症状，这个疑虑引发了人们对水产品食用安全的关注。为阐明水产品中嘌呤与尿酸生成的关系，为消费者提供科学的饮食指导，本项目组在前期采用反相离子对色谱法对食品中嘌呤含量检测的基础上，拟运用分析化学手段，系统分析水产品中嘌呤种类、含量及来源，找到水产品中嘌呤的特殊性，并利用禽类动物模型确定影响尿酸生成的关键嘌呤，研究其在渔获物中的代谢规律及其转化关键酶（如腺苷脱氨酶、鸟苷脱氨酶、黄嘌呤氧化酶等）的变化，同时探究水产品的贮藏与加工方式对嘌呤类化合物及其转化关键酶活性的影响，阐明水产品中嘌呤转化的机制，为消减尿酸的生成提供有效方法，此成果也可为其他食品中嘌呤的控制提供新的思路和理论支持。

嘌呤是尿酸生成的前体物质，食物中广泛存在。近年来，高尿酸血症和痛风发病率的逐年升高引发了人们对“过多摄入富含嘌呤的水产品是否会增加尿酸生成进而加剧痛风症状”这个疑虑的广泛关注。本项目组对水产品中嘌呤的含量分布、在贮藏与加工过程中的变化规律及嘌呤对个体尿酸生成的长效机制和即时效应进行了探究。首先建立了两种水产品中嘌呤检测的高效液相色谱方法，系统地分析了水产品中腺嘌呤、鸟嘌呤、次黄嘌呤和黄嘌呤的含量分布，进一步探究了其在贮藏加工中的变化规律，发现贮藏中对肾脏有显著损害作用的腺嘌呤逐渐降低，最易转化为尿酸的次黄嘌呤含量逐渐增加，而次黄嘌呤可通过水煮等方法进行消减。建立了持续、稳定的高尿酸血症动物模型，探究了摄入不同嘌呤对高尿酸血症及正常鹌鹑血尿酸水平影响的长效机制和即时效应，发现嘌呤作为尿酸的前体物质，在人体内转化为尿酸的长期效应和即时效应是不一致的。长期摄入腺嘌呤、鸟嘌呤、次黄嘌呤和黄嘌呤均使高尿酸血症和正常鹌鹑的血尿酸水平下降，摄入的嘌呤使个体腺苷脱氨酶酶活力及腺苷脱氨酶mRNA表达水平降低，导致外源性嘌呤生成的次黄嘌呤含量下降；同时，生物体内存在大量内源性的腺嘌呤及其衍生物，肝脏腺苷脱氨酶酶活力及mRNA表达水平的降低，也将显著影响内源性腺嘌呤的转化，因此，尿酸前体物质嘌呤的长期摄入反而使个体血尿酸水平下降，即嘌呤的摄入不是诱发痛风的原因，造成痛风的不仅仅是食物中所含嘌呤。通过嘌呤对鹌鹑血尿酸水平即时效应的研究发现，摄入嘌呤后，个体血尿酸水平增加，其中，次黄嘌呤作用最显著，鸟嘌呤和黄嘌呤次之，腺嘌呤最小。结合本项目测定的水产品中嘌呤含量及其在贮藏、加工中变化规律的研究，可以为痛风患者的饮食提供一定的理论指导。