Antagonism of astragalus polysaccharide on activity and nuclear translocation of glycogen synthase kinase 3βinvolved in regulation of glucose homeostasis / 中国生化药物杂志

ABSTRACT

Objective To observe the effect of astragalus polysaccharides ( APS) on glucose homeostasis regulation and focus on glycogen synthase kinase 3 beta (GSK3 beta) activity and subcellular localization (nuclear translocation).Methods HepG2 human hepatoma cells were cultured in vitro and treated with high glucose of different concentrations (30, 40 mM) to induce hepatocyte endoplasmic reticulum stress model, then acquire optimum operating concentration.The HepG2 cells were treated with APS of different concentrations (50, 100, 200, 400 μg/mL) to select the most effective concentration.The HepG2 cells were divided into seven groups with different treatment negative control group (C), positive control group (Tm), 30 mM high glucose-induced group (G30), 45 mM high glucose-induced group (G45), negative control+APS group (CA), positive control+APS group ( TA) and high glucose-induced+APS group ( GA).Effect of APS at different concentrations on proliferation activity of HepG2 cells were detected by MTT assay, transcription and shear levels of XBPlmRNA in HepG2 cells by quantitative real-time PCR, and phosphorylation levels of GSK3βin cytoplasm and nucleus by immunoblotting techniques.Results The optimum operating glucose concentration was 30 mM.The most effective APS concentration was 200μg/mL.The transcription and shear levels of XBPlmRNA in HepG2 cells of GA group were lower than those of G30 group ( P<0.05), respectively, but there were no significant differences between TA and Tm group.The phosphorylation levels of GSK3βin cytoplasm and nucleus of GA group were higher than those of G group(P<0.05), respectively, but there were no significant differences between TA and Tm group. Conclusion APS could improve hepatic steatosis, and its mechanism might be that APS inhibits the activity and nuclear localization of GSK3β, then alleviate endoplasmic reticulum stress.