茶多糖对KKAy糖尿病小鼠葡萄糖代谢和过氧化物增殖体激活型受体-γ活性的影响

目的:探讨绿茶的茶多糖(teapolysaccharides,TPs)对KKAy遗传性糖尿病小鼠血糖和过氧化物增殖体激活型受体γ(peroxisomeproliferator-activatedreceptorsgamma,PPAR-γ)活性的影响。方法:将TPs按500mg/kg剂量灌胃给予糖尿病KKAy小鼠,分别进行葡萄糖耐量试验,检测空腹血糖、餐后血糖、糖异生、胰岛素敏感性和果糖胺。体外CV-1细胞培养检测TPs对PPAR-γ活性的影响。结果:TPs不仅能改善KKAy糖尿病小鼠葡萄糖耐量,而且能降低空腹血糖、餐后血糖、果糖胺。TPs也能抑制糖异生和提高胰岛素敏感性。此外,TPs还能激活PPAR-γ,呈现剂量-效应关系。结论:茶多糖具有良好的降血糖作用,其机制可能是通过激活PPAR-γ而使其介导的胰岛素敏感性增高所致。

EFFECTS OF TEA POLYSACCHARIDES ON GLUCOSE METABOLISM AND PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR GAMMA IN KKAy TYPE 2 DIABETIC MICE

Objective: To investigate the effects of green tea polysaccharides (TPs) on glucose metabolism and the activity of peroxisome proliferator-activated receptor gamma (PPAR-γ) in KKAy type 2 diabetic mice. Methods: Glucose tolerance test, fasting and postprandial glucose, gluconeogenesis, and insulin sensitivity were investigated in type 2 diabetic mice with orally administered TPs at the dose of 500mg/kg for 4-10 w. Effect of TPs on activity of PPAR-γ was tested in vitro. Results: TPs could not only improve glucose tolerance, but also reduce fasting and postprandial blood glucose. In addition, TPs could inhibit gluconeogenesis and enhance insulin sensitivity in KKAy diabetic mice. TPs had also an effect of activating of PPAR-γ with dose-response. Conclusion: TPs have beneficial effect of lowering blood glucose in KKAy type 2 diabetic mice, which may be induced by enhancing insulin sensitivity by activating of PPAR-γ.