Immunoregulating Activity Of Porphyra Polysaccharide On Mice With Decreased Immunological Functions

PrefaceRecently, the study of marine drugs has become one of research focuses in the world. In fact, 'many marine food constituents not only have nutritional effects on animals, but also possess various medical properties. Marine algae contain a large amount of characteristic polysaccharides, some of which have been found to have immune - modulating effects, and is able to recovery and reinforce immune system. Some Polysaccharide from marine algae might stimulate the maturation, differentiation and proliferation of immunocyte, just as macro-phage ( Mφ) , nature - killer cell, and B Lymphocyte, might stimulate phagocyt-ic functions of phagocytosis and secreting cytokines, just as H₂ O₂, IL - 1, TNF, might increase peroxidase activity and phagocytosis of macrophage, is able to antagonize the decreased immunological functions induced by Cyclophospha-mide.Porphyra yezoensis is a kind of nutritional marine algae, which consist of some kinds of polysaccharides, such as fucose, lactose, carubinose, glucose and xylopyranose. Previous studies on biological activities of polysaccharide from P. yezoensis show that it might against the clotting, hypercholesterolemia, thrombus, hyperglycemia, phlegmasia, ulcer, and is able to against gene mutation , senility and radiation. It also have the functions of antagonizing the growing of cancer, and stimulating the proliferation of mice bone marrow cells and spleen cells.The purpose of this study is to investigate the protective effects of Porphyra Polysaccharide on immunity antagonizing the decreased immunological functions induced by immunoinhibitor, through making mice models of immunoinhibitor,then measuring the cytotoxic activity of NK cells, and the levels of interferon -γ(IFN -γ) and nitric oxide(NO) in the cultured supernatants of spleen cells. The result of this study will make an experimental basis for further research on PP antagonizing the decreased immunological functions in future.Materials and MethodsExtracting polysaccharide from Porphyra yezoensis by take - downing the fat, protein and freeze - drying. Porphyra Polysaccharide in different dosages (0.025g · kg-1,0.05g · kg-1,0. 15g · kg"1) were injected intraperitoneally into the C57BL/6 mice while those were treated with a certain amount of cyclo-phosphamide to induce immunological functions decreased. The mice with injunction of Cyclophosphamide or physiological saline solution alone as controls. After 7 days with one day - interval injection, the cytotoxic activity of NK cells, and the levels of interferon - 7 (IFN - 7) and nitric oxide ( NO ) in the cultured supernatants of spleen cells from different groups of mice were measured by the techniques of lactic dehydrogenase release reaction, ELISA and Griess reaction, respectively. The data obtained were analyzed statistically by Student' s t - test . All values were expressed as mean standard error of the mean (S. E. M. ) . Differences were considered significant at P <0. 05 or P <0. 01.ResultsThe cytotoxic activity of NK cells, and the levels of IFN - 7 and NO produced by spleen cells from the group of mice with the treatment of 0.15g · kg"1 of Porphyra Polysaccharide were all showed to be significantly higher than those from the mice injected cyclophosphamide alone (P<0. 05orP<0. 01). And there almost were the similar results for all of three tests being obtained between the groups with the treatment of 0.15 g · kg"1 of Porphyra Polysaccharide and Saline (control). Other Concentration groups have not shown statistic increase in contrast to the group injected cyclophosphamide alone.DiscussionPorphyra yezoensis has been used as food for many years. In fact, people have found its constituents not only have nutritional effects on animals, but also possess various medical values. P. yezoensis has been reported to consist of some kinds of polysaccharides, which have the functions antagonizing the hyper-glycemia, hypercholesterolemia, phlegmasia, senility and radiation obviously.Our study observed the immunoregulating activity of Porphyra Polysaccha-ride on mice with decreased immunological functions. It showed that the injection of cyclophosphamide might inhibit the cytotoxic activity of NK cells, and the levels of IFN - 7 and NO produced by spleen cells. The cytotoxic activity of NK cells, and the levels of IFN - 7 and NO produced by spleen cells from the group of mice with the treatment of 0. 15g kg'1 of Porphyra Polysaccharide were all showed to be significantly higher than those from the mice injected cyclophosphamide alone. And there almost were the similar results for all of three tests being obtained between the groups with the treatment of 0. 15g kg" of Porphyra Polysaccharide and Saline( control) .IFN - 7 is produced by Thl cell mainly. IFN - 7 has the strong activation of NK cells, and the conjugation between the IFN - 7 and the receptor of Macro-phage might recover and reinforce the producing levels of NO of Macrophage. The results showed Porphyra Polysaccharide is able to protect and activate Thl cell. It is reported that Porphyra Polysaccharide might directly induce the activation of Macrophage, and reinforce the producing levels of TNF - a. Thus, we deduce that synergistic action between the Porphyra Polysaccharide and IFN - 7 may induce the activation of Macrophage.IFN - 7, NK cell and Macrophage are the important part of cellular immunity and humoral immunity. We studied the immunoregulating activity of Porphyra Polysaccharide antagonizing the decreased immunological functions, and found that Porphyra Polysaccharide have satisfactory effect on recovering the immunological functions. The results showed Porphyra Polysaccharide may become the assistant treatment method of Cyclophosphamide. We will do more studying...