龙井茶多糖对ALX糖尿病模型小鼠氧化应激的影响

Effect of Polysaccharides from Longjing Tea on Oxidative Stress in Alloxan-induced Diabetic Mice

目的:探讨茶多糖对四氧嘧啶所致糖尿病小鼠氧化应激及胰岛β凋亡的影响。方法:热水抽提、Savag法脱蛋白的茶叶粗多糖经不同浓度酒精分级后获得4个组分,采用体外抗氧化方法筛选出抗氧化效果最强的组分TPS70。按ICR小鼠的血糖水平随机分为4组:空白对照组(CTG)、糖尿病模型组(DCG)、阳性药物组(PCG)与茶多糖组(TPG)。DCG,PCG与TPG小鼠采用腹腔注射四氧嘧啶复制高血糖模型,5 d后TPG组灌胃TPF70200 mg/kg,PCG灌胃消渴丸625 mg/kg,其它组小鼠腹腔注射生理盐水,35 d后检测各组小鼠肝糖原、谷胱甘肽还原酶、超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶和脂多糖的含量,并观察小鼠胰岛组织形态。结果:TPS70对糖尿病小鼠的脂多糖升高有显著的抑制作用(P<0.01),可使肝糖原值保持正常水平,血清中谷胱甘肽过氧化物酶以及肝组织中谷胱甘肽还原酶、超氧化物歧化酶、过氧化氢酶显著升高(P<0.01);胰岛组织细胞接近正常。结论:茶多糖可减轻ALX糖尿病小鼠的氧化应激,对糖尿病模型小鼠的胰岛组织有保护作用。

Objective： To investigate the effect of tea polysaccharides（TPS70） on oxidative stress and islet β-cells in diabetic mice induced by alloxan（ALX）. Methods： The polysaccharides were extracted from tea leaves by water extraction-alcohol precipitation, removal of protein and alcohol fractional prepared step by step, then four tea polysaccharide fractions with different molecular weight were obtained. The strongest component（TPS70） of the antioxidant effect was screened in vitro. ICR mice were divided into 4 groups according to blood glucose： control group（CTG）, diabetic control group（DCG）, positive control group（PCG） and tea polysaccharide group（TPG）. Alloxan was used to induce hyperglycemia models in mice of DCG, PCG and TPG, and the mice of TPG were treated with TPS70 at the dose of200 mg/kg by intragastric administration. At the end of experiment, the glycogen, lipopolysaccharide in mice, and glutathione reductase（GR）, superoxide dismutase（SOD）, glutathione peroxidase（GSH-Px） and catalase（CAT） in liver and serum were detected, and pancreas were observed. Results： Compared with that of the diabetic model group, TPS70 could significantly reduce the level of lipopolysaccharide in mice（P〈0.01）, and kept liver glycogen on normal level. In diabetic groups treated with TPS70, the activity of GR, SOD and CAT in liver and the activity of GSH-Px in serun were significantly increased compared with diabetic control group. The islet cells were similar to normal. Conclusion ： The TPS70 could improve antioxidant capacity of diabetic mice induced by alloxan, and protect the islet of the diabetic mice.