牛心柿叶多糖对糖尿病小鼠模型的降血糖作用

目的:观察牛心柿叶多糖对链脲佐菌素致糖尿病小鼠降血糖作用。方法:建立糖尿病小鼠模型,随机分为模型组、二甲双胍阳性组及牛心柿叶多糖低、中、高剂量组。ig给予牛心柿叶多糖0.3,0.6,1.2 g·kg-1,阳性组给予二甲双胍0.32g·kg-1,连续灌胃15 d。末次给药后葡萄糖氧化酶法测定空腹血糖(FBG);比色法测定血清中游离脂肪酸(FFA)和谷胱甘肽(GSH)水平及肝脏组织中总超氧化物歧化酶(T-SOD)活性和丙二醛(MDA)含量;Western blot法检测胰脏胰岛素受体底物-1(IRS-1)和组织的胰岛素受体(INSR)的表达。结果:与模型组比较,牛心柿叶多糖有效降低糖尿病小鼠的血糖(P<0.05);升高血清中GSH水平,同时降低FFA水平(P<0.05);提高肝组织中T-SOD水平,同时减少MDA含量(P<0.05);上调胰脏组织中IRS-1,INSR的蛋白水平(P<0.05)。结论:牛心柿叶多糖发挥有效的降血糖作用,机制可能与其对糖尿病小鼠肝脏组织脂质过氧化损伤的保护作用以及改善胰脏组织中INS信号转导通路有关。

Hypoglycemic Effect of Polysaccharide from Bovine Heart Persimmon Leaf in Diabetic Mice

Objective: To investigate the hypoglycemic effect of polysaccharide from bovine heart persimmon leaf in diabetic mice model induced by streptozotocin. Method: Diabetic mice model was established by injection of streptozotocin, then the mice were randomly divided into 5 groups: model group, dimethyldiguanide group (0.32 g·kg^-1), low-, medium-and high-dosage groups of polysaccharide of bovine heart persimmon leaf (0.3, 0.6, 1.2 g·kg^-1). The drugs were given to mice daily for 15 consecutive days. Fasting was carried out before administration for 12 h at the end of 15 days. The blood sample was collected via evulseing the mice eyes, and centrifuged to obtain serum for test. Glucose oxidase (GOD) was used to examine the index of glycemia for fasting plasma glucose(FBG); the levels of free fatty acids(FFA) and glutathione(GSH) in serum as well as the contents of total superoxide dismutase(T-SOD)and malondialdehyde(MDA) in liver tissue were tested by biochemical method. The expressions of IRS-1, INSR in pancreas were measured using Western blot analysis. Result: Compared to model control group, the polysaccharide could significantly decrease the level of blood-sugar in diabetic mice, the difference was statistically significant (P<0.05), and increase GSH level in serum, while reduce the NEFA level, difference was statistically significant (P<0.05). Compared with the model, the polysaccharide could also elevate T-SOD level in liver tissue, while reduce the content of MDA, difference was statistically significant (P<0.05). It also up-regulated the levels of INSR, IRS-1 protein in pancreatic tissue, difference was significant (P<0.05). Conclusion: The polysaccharide of bovine heart persimmon leaf can play the role of hypoglycemic activity though the mechanism may be related to the protective effect of lipid peroxidation injury in liver tissue and to improve INS signal transduction pathway in the pancreatic tissue of diabetic mice.