[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.


CONCLUSIONS
APS possesses immunotherapeutic effects on mice with type 1 diabetes mellitus through improving the cell- and humoral-mediated immunity.
Li
Ru-Jiang
RJ
Reproduction Centre, Medical School, Xi'an Jiao Tong University, Xi'an, Shannxi Province, China.
Qiu
Shu-Dong
SD
Chen
Hong-Xia
HX
Wang
Li-Rong
LR
D000818:Animals; D027885:Astragalus propinquus / Q000737:chemistry*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000276:immunology; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy* / Q000276:immunology; D007155:Immunologic Factors / Q000494:pharmacology / Q000627:therapeutic use*; D007371:Interferon-gamma / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D047495:PPAR gamma / Q000378:metabolism; D011134:Polysaccharides / Q000494:pharmacology / Q000627:therapeutic use*
D007155:Immunologic Factors; D047495:PPAR gamma; D011134:Polysaccharides; D015847:Interleukin-4; D007371:Interferon-gamma