黄芪多糖对2型糖尿病模型大鼠餐后1 h血糖的影响

目的探讨黄芪多糖(APS)对2型糖尿病(T2DM)大鼠餐后1 h血糖的影响。方法利用高脂饮食联合一次性腹腔注射30 mg·kg^-1链脲佐菌素(STZ)构建T2DM大鼠模型。将正常组大鼠分为对照组(NC组)和黄芪多糖给药组(NC+APS组),模型组大鼠分为对照组(T2DM组)和黄芪多糖给药组(T2DM+APS组),共4组,每组6只。空腹状态下,对正常组大鼠和T2DM模型组大鼠分别灌胃淀粉水溶液(7.5%Starch)和淀粉+黄芪多糖混合溶液(7.5%Starch+700 mg·kg^-1APS),以及葡萄糖水溶液(7.5%GLU)和葡萄糖+黄芪多糖混合溶液(7.5%GLU+700 mg·kg^-1APS)。采集灌胃0(空腹)、15、30、45、60 min的血清标本测定其血糖值,绘制血糖变化曲线,计算血糖变化(Δ血糖)峰值、血糖与时间的曲线下面积增值(IAUC)。采用3,5-二硝基水杨酸比色法(DNS法)测定0.20%、0.05%及0.0125%3种浓度的黄芪多糖对α-淀粉酶活性的体外抑制作用。结果(1)淀粉灌胃实验:与对照组比较,黄芪多糖给药组的正常大鼠(15、30 min)和T2DM大鼠(30、45 min)的血糖值明显降低,Δ血糖达峰时间均从餐后30 min提前到餐后15 min,且Δ血糖峰值和IAUC均显著降低,差异具有统计学意义(P<0.05)。(2)葡萄糖灌胃实验:与对照组比较,黄芪多糖给药组正常大鼠(30、45 min)的血糖值及Δ血糖峰值显著降低,差异具有统计学意义(P<0.05),IAUC虽有降低趋势,但差异无统计学意义(P>0.05);T2DM大鼠血糖值、Δ血糖峰值及IAUC的差异均无统计学意义(P>0.05),但Δ血糖达峰时间从餐后30 min提前到餐后15 min。(3)0.20%、0.05%及0.0125%3种浓度的黄芪多糖对ɑ-淀粉酶活性的抑制率分别为(8.50±1.13)%,(7.10±0.96)%和(6.30±0.05)%,其抑制作用呈一定剂量依赖关系。结论黄芪多糖可以明显降低T2DM模型大鼠摄食淀粉后1 h的餐后血糖,其机制可能与其对α-淀粉酶活性的抑制有关。

Effect of Astragalus Polysaccharides on Postprandial 1 Hour Blood Glucose in Type 2 Diabetic Rats

Objective To investigate the effect of astragalus polysaccharides(APS) on postprandial 1 h bloodglucose of rats with type 2 diabetes mellitus(T2 DM). Methods A high fat diet combined with a single intraperitonealinjection of 30 mg·kg^-1 streptozocin(STZ)was used to induce T2 DM rat model. Normal group rats were divided intocontrol group(NC group)and APS administration group(NC + APS group);model group rats were divided intocontrol group(T2 DM group)and APS administration group(T2 DM + APS group). There are 6 rats in each group.Under fasting conditions,the normal rats and T2 DM rats were respectively given an aqueous starch solution(7.5%Starch)and a starch+APS mixture solution(7.5% Starch+700 mg·kg^-1 APS),and a glucose solution(7.5% GLU)anda glucose+APS mixture solution(7.5% GLU+700 mg·kg^-1 APS). Blood samples of rats were collected after 0,15,30, 45 and 60 minutes of intragastric administration to obtain the blood glucose value for blood glucose curve,calculate the peak of blood glucose change(Δblood glucose)and the area increase under the curve of blood glucose(IAUC). The 3, 5-dinitrosalicylic acid colorimetric assay was used to observe the inhibitory effect of differentconcentrations of APS(0.20%,0.05%,0.012 5%)on the α-amylase activity in vitro. Results(1)Starch gavageexperiment:compared with the control group,the blood glucose levels of normal rats(15,30 min)and T2 DM rats(30, 45 min) in the APS administration groups were significantly reduced, the Δpeak blood glucose time wasbrought forward from 30 minutes to 15 minutes after the meal, and the Δblood glucose peak and IAUC weresignificantly reduced, and the difference was statistically significant(P < 0.05).(2)Glucose gavage experiment:compared with the control group,the blood glucose value and Δblood glucose peak of the normal rats(30,45 min)of the APS administration group were significantly reduced,and the differences were statistically significant(P <0.05). The IAUC showed a downward trend with no statistically significant difference(P > 0.05);there were nosignificant difference in blood glucose,Δblood glucose peak,and IAUC in T2 DM rats(P > 0.05),but the Δbloodglucose peak time was brought forward from 30 minutes to 15 min after a meal.(3)Inhibition rates of amylase-activity by APS at three concentrations of 0.20%,0.05%,and 0.012 5% were(8.50±1.13)%,(7.10±0.96)%,and(6.30 ± 0.05)%, respectively, and the inhibitory effect showed a dose-dependent manner. Conclusion APS cansignificantly reduce postprandial 1 h blood glucose after T2 DM rats ingesting starch. The mechanism may be relatedto inhibiting the digestion and absorption of starch by inhibiting the activity of α-amylase.