Study On The Immunomodulatory Effects Of Two Seaweed Polysaccharides

China is a big ocean country with abundant seaweed resources.As an important component of algal cells,polysaccharides have been reported to have a variety of biological activities.The diversity of biological activities of polysaccharides from brown algae depend on the rich resources of brown algae.The biological activities that have been found include immune regulation,antiviral,antioxidant,anti-tumor,anti-bacterial and fat-reducing functions.In this study,the biological activities of immune regulation of low molecular weight fucoidan(LMWF)and algiane were explored.There are two parts of research work as follows:(1)In this study,the immune activation and mechanism of LMWF improving mouse macrophage RAW264.7 were studied.The MW distribution of the fucoidan extracted from New Zealand Undaria pinnatifida was determined by high-performance gel permeate chromatography(HPGPC),and the molecular weight of LMWF is less than 10 kDa.It was found that LMWF could effectively promote the production of NO,iNOS,TNF-?,IL-6 and other immune mediators in RAW264.7 cells in a concentration-dependent way.Further investigation revealed that LMWF can significantly activate NF-?B signaling pathway and MAPK signaling pathway in RAW264.7 cells.When treated with inhibitors of NF-?B and MAPK signaling pathways,the effect of LMWF on the secretion of immune mediators by RAW264.7 cells was significantly inhibited.(2)In this study,alginate inhibited OVA induced allergic reactions in mice.The results showed that alginate could effectively inhibit allergic diarrhea in mice induced by OVA.To protect the integrity of intestinal epithelial villi in mice and inhibit the degranulation of mast cells in jejunum.The levels of IgE,histamine and IL-4 in serum of mice were decreased,and the levels of IFN-y were increased.The number of Treg in mouse spleen tissues was maintained.The differentiation of ThO cells into Th2 cells was inhibited.The ratio of Thl cells to Th2 cells was up-regulated.The study found that both polysaccharides have immunomodulatory activity,and the results of the study provide theoretical support for the development of both polysaccharides into drugs or health care products with immunomodulatory functions.With the development and utilization of algal resources,the research on algal polysaccharides is expected to become one of the hot spots in the field of life science in the future.