Astragalus Polysaccharide Improves Insulin Sensitivity via AMPK Activation in 3T3-L1 Adipocytes

• Published in: Molecules (Basel, Switzerland) Vol. 23; no. 10; p. 2711
• Main Authors: Zhang, Ruixin, Qin, Xuze, Zhang, Ting, Li, Qian, Zhang, Jianxin, Zhao, Junxing
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21.10.2018; MDPI
• Subjects: 3T3-L1 Cells - drug effects; Adipocytes; Adipocytes - drug effects; adipogenesis; AMP-Activated Protein Kinases - genetics; AMPK; Animals; Antigens; Astragalus Plant - chemistry; astragalus polysaccharide; Cytotoxicity; Dehydrogenases; Diabetes; Fatty acids; Gene Expression Regulation, Enzymologic - drug effects; Glucose; Glucose - metabolism; Humans; Insulin Receptor Substrate Proteins - genetics; Insulin Resistance; insulin sensitivity; Kinases; Metabolism; Mice; Musculoskeletal system; Phosphorylation; Polysaccharides - chemistry; Polysaccharides - isolation & purification; Polysaccharides - pharmacology; proliferation; Proteins; Traditional Chinese medicine; insulin sensitivity; AMPK; adipogenesis; proliferation; astragalus polysaccharide
• DOI: 10.3390/molecules23102711
• ISSN: 1420-3049

Astragalus polysaccharide (APS) is an important bioactive component of Astragalus membranaceus which is used as an anti-diabetes herb in traditional Chinese medicine. The objective of this study was to investigate the effects and mechanisms of APS on insulin-sensitizing of adipocytes. Mouse 3T3-L1 preadipocytes were used as a model. The results showed that APS increased preadipocytes proliferation in a dose dependent manner, and 0.1 μg/mL APS sufficiently increased Proliferating Cell Nuclear Antigen (PCNA) content (p < 0.01). Moreover, APS enhanced intracellular lipid accumulation and mRNA expression of proliferator-activated receptor γ (PPARγ, p < 0.01), CCAAT/enhancer binding protein α (C/EBPα, p < 0.01) and fatty acid binding protein (aP2, p < 0.01). As expected, corresponding protein contents were elevated. Importantly, APS increased 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino)-2-Deoxyglucose (2-NBDG) uptake (p < 0.01). Meanwhile, both mRNA and protein content of glucose transporter 4 (Glut4) were elevated by APS (p < 0.01). The APS treatment enhanced tyrosine phosphorylation of insulin receptor substrate 1 (IRS1, p < 0.05) and phosphor-Akt content (p < 0.01). Besides, phosphorylated AMP-activated protein kinase (AMPK) content was increased in the APS treated cells (p < 0.01). Taken together, APS improved insulin sensitivity by enhancing glucose uptake, possibly through AMPK activation. These results suggested that APS might be a therapeutic candidate for insulin resistance.