桑叶治疗2型糖尿病药效及其机制研究

Effect and Mechanism of Morus alba for Treating Non-insulin-dependent Diabetes Mellitus

目的:探讨桑叶对KKAy2型糖尿病小鼠血糖、胰岛素(Ins)敏感性及胰岛细胞Toll样受体TLR2,TLR4 mRNA表达的影响,初步探讨其降糖机制。方法:KKAy小鼠随机分为模型组、桑叶高、中、低剂量组(分别相当于含生药3.0,1.5,0.75 g.kg-1)和二甲双胍组(0.4 g.kg-1)。另设10只C57BL6小鼠为正常对照组。各给药组分别喂饲不同浓度的药物,模型组与对照组均ig等容量自来水。连续4周,末次给药后1 h取血,测定小鼠空腹血糖(FPG)、空腹胰岛素(FIns)含量,分析胰岛素敏感性的变化情况。提取小鼠胰岛细胞总RNA,Real time-PCR法测定胰岛细胞TLR2,TLR4 mRNA表达。结果:桑叶各剂量能明显降低KKAy小鼠的FPG(P<0.05或P<0.01)、降低血清Ins含量(P<0.05或P<0.01),明显降低KKAy小鼠胰岛素抵抗指数与胰岛细胞TLR2,TLR4 mRNA表达(P<0.05或P<0.01)结论:桑叶有较好的降血糖、增强胰岛素敏感性等作用,其作用可能与减弱胰岛细胞TLR2,TLR4表达、抑制炎症过程有关。

Objective： To study the effect and pharmacological mechanism of Morus alba for trating non- insulin-dependent diabetes mellitus. Method： The KKAy mice were randomly divided into 5 groups： model group, Morus alba high, middle and low dose groups （3, 1.5, 0.75 g .kg-1 ） and metformin group （0.4 g kg-1 ）. Model group and control group animals were administrated with the same volume of tap water. Four weeks later, the contents of fasting plasma glucose （FPG）, fasting plasma insulin （Fins） were observed, and the insulin sensitivity of mice was analyzed. Total RNA was extracted from island cells and the content of TLR2 and TLR4 was evaluated with Real time-PCR method. Result： Morus alba of different doses could obviously decrease the amount of FPG （ P 〈 0.05 or P 〈 0.01 ） , decrease the content of insulin, reinforce the sensitivity of rat to exogenous insulin （P 〈 0.05 or P 〈0.01 ） and decrease the expression of TLR2, TLR4 of KKAy mice islet cells. Conclusion： Morus alba had significant effect to decrease FPG and improve the sensitivity to exogenous insulin, its effects may be related to the decrease in expression of TLR2, TLR4 and inhibition of inflammation.