黄芪多糖对1型糖尿病小鼠的免疫调节作用

目的：探讨黄芪多糖（Astragalus polysaccharide,APS）对1型糖尿病的免疫调节作用。方法：以低剂量链脲菌素（streptozotocin,STZ）多次腹腔注射,建立1型糖尿病小鼠模型,每天分别用100、200、400mg/kg APS或1ml生理盐水腹腔注射,15d、30d时将小鼠处死。以形态学方法观察胰岛炎症,以放射免疫法检测血胰岛素自身抗体,以放射性同位素氚标记的嘧啶核苷（^3H]thymidine incorporation,^3H-TdR）掺入法研究脾细胞对刀豆蛋白A（concanavalin A,Con A）的增殖反应,以酶联免疫吸附（enzymelinkedi mmunosorbent assay,ELISA）法检测脾细胞白细胞介素-4（interleukin-4,IL-4）和干扰素-γ（interferon-γ,IFN-γ）的分泌,以蛋白免疫印迹（Western-blot）法检验脾过氧化物酶体增殖物激活受体γ（peroxisome proliferator-activated receptorγ,PPARγ）的表达。结果：与对照组比较,APS处理组胰岛炎症减轻,血胰岛素自身抗体水平下降,脾细胞对Con A的增殖能力减弱,Th1/Th2分泌因子比值下调,脾PPARγ水平提高,所有这些均与APS的剂量和使用持续时间密切相关。结论：APS可通过调节体液免疫和细胞免疫治疗小鼠1型糖尿病。

Immunomodulatory effects of Astragalus polysaccharide in diabetic mice

OBJECTIVE: To study the immunomodulatory effects of Astragalus polysaccharide (APS) in type 1 diabetic mice. METHODS: A mouse model of type 1 diabetes mellitus was established by intraperitoneal injection of multiple low dose streptozotocin (MLD-STZ). The diabetic mice were intraperitoneally administered 100, 200, 400 mg/kg APS or 1 ml normal saline (NS) every day respectively, then the diabetic mice were sacrificed after 15 or 30 days of treatment. The effect of APS on insulitis was determined via pancreatic histological analysis. Serum insulin autoantibody (IAA) levels were measured by radio-immunoassay (RIA). Proliferation ability of splenocytes to concanavalin A was tested by using (3)H] thymidine incorporation assay. The levels of cytokine interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) secreted by splenocytes were determined by enzyme linked immunosorbent assay (ELISA) method, and the expression of peroxisome proliferator-activated receptor gamma (PPARgamma) in spleens was characterized using Western-blot analysis. RESULTS: Attenuated insulitis, down-regulation of the serum IAA levels and Th1/Th2 cytokine ratio, decrease of the proliferation ability of splenocytes to concanavalin A, and up-regulation of the PPARgamma levels in spleens showed a significant time- and dose-dependent response to APS treatment as compared with the NS-treated group. CONCLUSION: APS possesses immunotherapeutic effects on mice with type 1 diabetes mellitus through improving the cell- and humoral-mediated immunity.