Regulating Effects Of Sea Cucumber And Sea Cucumber Fucoidan On Mucosal Immunity In Mice

Chemotherapy drug, such as cyclophosphamide is a kind of clinical drugcommonly used in cancer treatment. Chemotherapy drug has the effect to kill tumorcells, but it kills the rapid proliferated normal cells, like cells in gastrointestinal tract andrespiratory tract mucosa simultaneously, which causes the damage of body mucosalimmune function. Drugs used for the treatment of mucosal immune damage have certainlimitations. Food is a kind of material which has various effects, almost no toxicity, andcontacts with the digestive tract mucosa directly. Thus, it becomes the primary sourse toprotect mucosal immune. Sea cucumber with long research history is a kind of preciousmarine biological resource. Sea cucumber contains many kinds of bioactive substances,such as sea cucumber polysaccharides, saponin, active peptide, phospholipids, etc. It hasbeen proven that sea cucumber exhibits various biological activities includingimmunoregulatory, anti-tumor, anti-coagulation and improving lipid metabolism. Thisresearch mainly discussed the protective effects of sea cucumber and one of its activematerials, sea cucumber fucoidan on cyclophosvnamide-induced mucosal immune injury.The achivement of this study will provide technical support to perfect sea cucumbernutrition evaluation system, and supply theoretical basis for the development offunctional food with sea cucumber polysaccharide. All these will promote the deeperdevelopment and utilization of marine biological resources.This paper mainly consists of three parts:1. Research of the protective effects about four common species of sea cucumberson mice intestinal mucosal immunity. Building intestinal mucosal immunity damagedanimal model induced by cyclophosphamide, conducting gavage experiment withApostichopus japonicas, Isostichopus badionotus, Thelenota ananas, and Acaudinamolpadioides, and evaluating the effects of sea cucumber on intestinal mucosalimmunity by detecting the intestinal mucosal immune related indexes. Our dataindicated that sea cucumber could protect intestinal mucosa from cyclophosphamide-induced damage, including increasing the immune organ index toraise the overall immunity, increasing villus length and V/C ratio to restore intestinaltissue structure and keep the comprehensive function, and regulating the secretion ofIFN-γ and IL-4to improve the balance of Th1/Th2. Moreover, sea cucumber couldpromote the secretion of intestinal mucosal immune effect factors SIgA. Besides, theeffects of Apostichopus japonicas and Thelenota ananas were more obvious in thesefour sea cucumbers, which may be related to their higher polysaccharide content.2. Research of the protective effects about sea cucumber on mice respiratory tractmucosal immunity. This research conducted reference to the handling methods anddosage of people eating sea cucumber. Using cyclophosphamide induced mucosalimmunity damaged animal model to detecte the innate and acquired immune factors inrespiratory tract and study mechanism further. Research showed that sea cucumber couldprotect respiratory tract mucosa from cyclophosphamide-induced damage, includingimproving the expression of lysozyme to enhance the innate immune, promoting thesecretion of SIgA to enhance the acquired immune. Further research indicated that seacucumber could improve the expression of IgA and pIgR, accordingly advance thesecretion of SIgA, and then improve the immune function of the respiratory tractmucosa.3. Research of the protective effects about sea cucumber and sea cucumberfucoidan on mice intestinal mucosal immunity. First of all, Intestinal immune protectiveeffects of SC-FUC with different molecular weight were evaluated by detecting theintestinal mucosal immune related indexes. Results showed that SC-FUC and itsenzymatic degraded fragments could increasing the immune organ index, restoreintestinal tissue structure, improve the secretion of cytokines to keep the balance ofmucosal immune, and increase the intestinal mucosal immune antibody IgA. Secondly,the relationship of effects distinctiveness about different molecular weight SC-FUC andtheir digestion and absorption efficiency were studied by detecting the serum fucusecontent in mice. Results indicated that the digestion and absorption efficiency were higerin SC-FUC with lower molecular weight. So the effects of different molecular weightSC-FUC may be related to its digestion and absorption efficiency. Finally, the mechanism which SC-FUC improve the expression of IgA were further studied. Itdemonstrated that SC-FUC could promote the immune function of macrophages,activate NF-κB signal passway by enhancing the expression of TLRs, stimulate theexpression of IL-6and IL-10, and then boost the IgA expression to improve theintestinal mucosal immune function.In conclusion, this study showed that sea cucumber and sea cucumber fucoidancould improve the mucosal immune damage induced by cyclophosphamide. Amongthese, Sea cucumber species with more polysaccharide content, like Apostichopusjaponicas and Thelenota ananas and sea cucumber fucoidan with appropriate lowmolecular weight,50KDa-500KDa in this study worked better. This study provided atheoretical basis for the further development and utilization of sea cucumber and seacucumber polysaccharide.