| Nostoc sphaeriods is one kind of edible filiform cyanobacteria. It contains higher content of protein, but lower level of fat, and all essential amino acids for human. Moreover, it is rich in vitamins(VB1, VB2, VC, etc.), mineral elements, and a variety of special biological active substances that can enhance the immune capacity of human. Now it has become a popular health care food and nourishment. The analysis of nutrient components and the evaluation of immune function of Nostoc not only can provide a scientific basis for the evaluation of Nostoc sphaeriods as an edible alga and health care products, but also supply the theoretical basis for developing it as a high-end healthy food by a large scale of outdoor culture of Nostoc sphaeriods.Nostoc sphaeriods used in the present study was obtained by batch ventilative culture on the laboratory conditions with the CT medium. The obtained biomass of Nostoc was air dried naturally under the laboratory conditions, smashed, and then quantificationally added to the ordinary food of mouse at the rate of 0.5% Nostoc of mouse total food(5 000 mg · kg-1).Briefly, the treated mosue was intraperitoneally injected cyclophosphamide(CY) dissolved in physiological saline at a dose of 80 mg · kg–1 bw to induce immunosuppression, which was enhanced by injecting the dose of cyclophosphamide 14 d later, while the control mcie received the same volume of saline solution by intraperitoneal injection. The mice were randomly divided into four groups, i.e., 1) the control group(CK) in which the mice intraperitoneally injected saline solution and fed the normal food; 2) the cyclophosphamide-exposed group(CY) in which the mice intraperitoneally injected cyclophosphamide and fed the normal food; 3) the Nostoc group(NS) in which the mice intraperitoneally injected saline solution and fed the normal food but suppied with Nostoc; 4) the CY+NS group in which the mice intraperitoneally injected cyclophosphamide and fed the normal food but suppied with Nostoc. After 7, 14, and 28 d of treatment, respectively, the growth, biochemical and immunological indexes were determined and the main results obtained in this study were as follows.1. Both the body weight and body length of mice in the NS groups were higher than that in control group after 7, 14, and 28 d of treatment, suggesting that feeding Nostoc can significantly promote the growth of mice, and may have stimulating effect on the immune organs of mice.2. The white blood cell numbers of mouse serum from the NS group were remarkably higher than those from the control group, although they were still within the normal range according to the standard of clinical haematology, and the phagocytosis rate and index of macrophage cell from the NS group were siginificantly higher than those from the control group, suggesting that Nostoc can enhance the non-specific immune function of mouse.3. The conversion rates of spleen lymphocyte, and the contents of Ig G, IL-2, IL-4, IL-6, TNF-α, and IFN-γ in serum from the NS group were higher than those from the CY group or control group, suggesting that Nostoc sphaeriods can adjust specific immune function of mouse.4. The total antioxidant capacities in mouse serum from the CY + NS group were higher than those from the CY group thoughout the period of total experiment. Moreover, the total antioxidant capacities in mouse serum from the NS group were also higher than those from the control group, suggestiong that Nostoc can significantly enhance the total antioxidant capacity of mouse.5. The results of histopathological examinations showed that Nostoc feeding had no damage to the tissue and organ of mouse, for example liver, spleen, kidney and thymus. Futhermore, Nostoc might have inhibitory and restored effects on the injury in mouse caused by cyclophosphamide.In conclustion, our results indicate that feeding mouse with Nostoc for long term can promote the growth, enhance the total antioxidant capacity and the immune functions of mouse. |
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