The Effects And Mechanism Of Sea Cucumber And Its Bioactive Components On Hyperuricemia In Mice

Sea cucumber is an important marine food and drug resource, which contains a variety of bioactive components, such as polysaccharides, saponin, collagen proteins, and cerebroside. Previous studies have shown that t sea cucumber is proved to exhibit various biological activities, including anti-tumor, antioxidant, immunomodulatory, anti-hyperlipidemia.In this study, the whole sea cucumber and its isolated bioactive components (sea cucumber saponin, sea cucumber polysaccharides, sea cucumber cerebroside, Echinoside A) were used to investigate their effects on metabolism of uric acid in food-induced hyperuricemia mice and spontaneous obesity (db/db) mice. And the mechanism was also preliminary studied. The main researches in this thesis were listed below:1. The hyperuricemia model was induced by dietary yeast extract powder. The effect of Apostichopus japonicus (Aj), Cucumaria frondosa (Cf) and Pearsonothuria graeffei (Pg) on uric acid metabolism in yeast extract powder induced hyperuricemia mice were investigated. All of them were suggested to possess a potent anti-hyperuricemic effect on yeast extract powder induced hyperuricemia. After 9 days’feeding, the Aj, Cf and Pg groups decreased serum uric acid level by 20.4%(P< 0.01),37.2%(P<0.01) and 37.5%(P<0.01) respectively. After 14 days’feeding, serum uric acid level was reduced by 33%(P<0.01),42.3%(P<0.01) and 45.3%(P <0.01) respectively. The further study showed that the anti-hyperuricemia effect of the three kinds of sea cucumbers were related to inhibiting the activities of the hepatic xanthine oxidase (XOD) and adenosine deaminase (ADA).2. Then, the effects of major bioactive components in sea cucumber, saponin, polysaccharides and cerebroside on uric acid metabolism in yeast extract powder induced hyperuricemia mice were studied. And the mechanism was revealed in gene transcription levels. After 9days’feeding, the results showed that all of them could significantly decrease serum uric acid. After 14 days’feeding, the serum uric acid levels in sea cucumber saponin (SCS), sea cucumber polysaccharides (PSC)and sea cucumber cerebroside (SCC) feeding groups were decreased by 21.7%(P<0.05),12%(P<0.01),) and 16.9%(P<0.05), respectively. And all of them could inhibit hepatic XOD and ADA activities, and down-regulate the mRNA levels of hepatic XOD and ADA. Furthermore, renal glucose transporter 9 (GLUT9), which is the important transporter in the process of the reabsorption of uric acid was decreased in SCS and PSC groups. Moreover, all of the three kinds of bioactive components could up-regulate the mRNA levels of renal organic cation and carnitine transporters (OCTs and OCTNs) to improve the renal fuction.3. Finally, the effects of sea cucumber saponin—HA on uric acid metabolism and renal fuctions in obesity (db/db) mice were investigated. Dietary HA could obviously decrease serum uric acid level by 18.2%(P<0.05)with no down regulation on mRNA levels of hepatic XOD and ADA. Furthermore, HA was found to up-regulate the mRNA levels of renal organic anion transporter 1 (OAT1), increase the secretion of uric acid. And the up-regulations of mRNA levels of OCTs and OCTNs showed the improving of renal function.In this study, we investigated the effects of the sea cucumber and its bioactive components on hyperuricemia mice, made a preliminary study of the mechanism, and enriched the research fields of sea cucumber. These results provide the scientific basis for the comprehensive utilization of sea cucumber and new marine drugs discovery.