Astragalus Polysaccharides: An Effective Treatment for Diabetes Prevention in NOD Mice

Abstract

Background: Type 1 diabetes mellitus (DM) is a chronic autoimmune disease that is related to the disequilibrium state of Th1 and Th2 subgroups of helper T lymphocyte (Th) and their cytokines. Astragalus polysaccharides (APS) are bioactive components extracted from one of the traditional Chinese herbs, used to enhance the function of human immune system.

Objective: To investigate the effects of APS on preventing type 1 DM and Th1/Th2-subtype cytokines, we compared the results of administration of APS and normal saline (NS) on non-obese diabetic (NOD) mice.

Subjects and Methods: APS or NS was administered to 4-week-old mice at a dose of 2.0 g/kg per day for 10 weeks. At 40 weeks, blood glucose, serum C-peptide (C-P) and GAD antibody were measured; pancreas was examined histologically; the intra-islet lymphocyte infiltration and T lymphocyte subsets in the spleen were analysed; the gene expression of IL-1β, IL-2, IL-6, IL-12, TNF-α, INF-γ, IL-4, IL-5, IL-10, TGF-β, Bcl-2, SOD, Fas and iNOS were measured by RT-PCR.

Results: The results showed that APS-administered NOD mice had a lower incidence rate of type 1 DM, lower serum C-P level, better histologic findings of pancreatic islets, and a lower D4+/CD8+ ratio of T lymphocytes from the spleen and the infiltrated islets. RT-PCR analysis showed gene expression levels are lower in IL-1β, IL-2, IL-6, IL-12, TNF-α, INF-γ, Fas, iNOS, and higher in IL-4, IL-5, IL-10, TGF-β, Bcl-2, SOD in the pancreatic tissue from APS-administered NOD mice as compared to the NS group.

Conclusions: These results demonstrated the effects of Astragalus polysaccharides on the prevention of type 1 DM in NOD mice by correcting the imbalance between the Th1/Th2 cytokines.

astragalus polysaccharides - diabetes - immunology - gene expression

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