Experimental Study About The Immunomodulatory Mechanism Of PAP On Immunosuppressed Mice Which Is Poisoned By Cadmium

Objectives: Explore the immunosuppressed mice of the immunomodulatory effects and its possible mechanism of action, which is poisoned by cadmium, so as to provide experimental evidence for the clinical application of PAP in the aspect of prevention and treatment of cadmium toxicity.Methods: 1.Extract polysaccharides(PAP) which yield the Tianzhu area of Gansu province in the autumn, and make the quantitative and qualitative identification for it. 2.After adaptive feeding for 14 days, the health males Kunming mice were injected by tail vein with cadmium solution of 1.2 mg/kg·d for 14 days, by using flow cytometry to detect spleen T lymphocyte subsets, after the success of modeling, 70 males Kunming mice were randomly divided into seven groups, 10 mice in each group. The model group: mice of the model group were injected by tail vein with cadmium solution of 1.2 mg/kg·d for 14 days. PAP pre-treatment group: mice of PAP pre-treatment group were injected by enterocoelia with PAP solution of 100 mg/kg, every other day, continuous injection for four times(the second day after the last injection), then injected by tail vein with cadmium solution of 1.2 mg/ kg·d for 14 days. PAP high, medium and low dose group: Like with the model group, after injection of cadmium solution for 14 days, PAP solution with 50,100,200 mg/kg were given respectively for the mice of PAP low, medium and high dose groups, every other day, continuous injection of 4 times. Blank control group and cyclosporin A group: mice of blank control group were injected by tail vein with an equal volume of 0.2 mL·d-1saline, mice of cyclosporin A group were injected by tail vein with CSA solution of 1.5 mg/ kg·d,mice of the above two groups were injected continuously for 14 days. After the last injection, 4hours later, mice of each group were injected by enterocoelia with 6 % starch broth for 1mL, once a day, continuous injection for three times. 30 minutes before death, mice of each group were injected by enterocoelia with of 5% chicken erythrocytes. After 30 minutes, take blood from eyeball, separation of serum, and take peritoneal fluid about 5 ml. After sacrificed by cervical,extract the thymus, spleen, and weighed, take the colon, the thymus and spleen, and fixed them with 4% formalin solution to be tested. Observe the pathological changes of the spleen, colon pathology by HE staining; Observe the thymic T cell fluorescence of percentage of positive byindirect immunofluorescence; By using flow cytometry to detect the percentage of CD4+, CD8+and the ratio of CD4+/CD8+; By using ELISA to measure the content of IL-2, IL-10 and IFN-γ in the serum; Observe the mouse peritoneal macrophage’ changes of phagocytic function by using optical microscopy.Results: 1.The polysaccharides(PAP) which yield the Tianzhu area in autumn, its content of monosaccharides is more 2.03 % and the major monosaccharides are glucose and arabinose. 2.Model group and cyclosporin A group compared with blank control group is significant difference(P<0.05), Spleen, thymus index and the spleen T lymphocyte’ percentage of CD4+ are decreased significantly, the percentage of CD8+ is increased significantly, immune cells that of the tissue of thymus, spleen and colon are damaged, thymic T cell’CD4+ fluorescence of percentage of positive,the content of IL-2 and IFN-γ in the serum, and phagocytic function of macrophage are decreased significantly, however, thymic T cell’CD8+ fluorescence of percentage of positive and the content of IL-10 in the serum are increased significantly. 3. Model group compared with cyclosporin A group is not statistically significant(P ≥ 0.05). 4. PAP pre-treatment group, PAP medium and high dose groups compared with model group, the pathology of spleen and colon tissue is close to norm,thymus tissue’ recovery is not obvious. Thymic T cell’CD4+ fluorescence of percentage of positive,The percentage of T lymphocytes CD4+, the content of IL-2 and IFN-γ in the serum, and phagocytic function of peritoneal macrophage are increased significantly(P<0.05 or P<0.01).However, thymic T cell’CD8+ fluorescence of percentage of positive, the percentage of T lymphocytes CD8+, and the content of IL-10 in the serum are decreased significantly. PAP low dose group is not statistically significant(P ≥0.05). PAP pre-treatment group compared with PAP medium dose group is not statistically significant(P≥0.05), PAP high dose group compared with PAP pre-treatment group is significant difference(P<0.05).Conclusions: 1. The polysaccharides(PAP) which yield the Tianzhu area in autumn, its content of monosaccharides is more than 2%, and the major monosaccharides are glucose and arabinose.2. PAP can enhance the cellular immune function of immunosuppressed mice, its mechanism is related to protect the mice immune organs, enhance phagocytic function of peritoneal macrophage of mice, and adjust the synthesis level of key cytokines IL-2, IFN-γ and IL-10 of differentiation caused by the murine T cells which are poisoned by cadmium, its role is positively related with the concentration of PAP.