以链脲佐菌素造模糖尿病小鼠为研究对象，以二甲双胍作为参照，探索了乌饭树树叶多糖降血糖的机理。结果表明，灌胃乌饭树树叶多糖6周，VBTLP高剂量组小鼠血清胰岛素(INS)含量提高了4.38%，小鼠胰岛β细胞功能和胰岛素分泌指数分别比模型组提高了83.40%和63.83%；小鼠肝脏的抗氧化能力明显提高，其中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活力分别增加了2.49%、1.74%和6.04%，肝丙二醛(MDA)含量降低了6.12%（p<0.05）；从小鼠的胰岛组织切片分析推测高剂量乌饭树树叶多糖对小鼠β细胞结构有明显的修复作用。从以上实验结果可推测，乌饭树树叶多糖降血糖机理体现在促进胰岛素分泌、修复糖尿病小鼠受损胰岛β细胞和提高糖尿病小鼠抗氧化能力三个方面。

The mechanism of hypoglycemic activity of Vaccinium bracteatum Thunb. leaf polysaccharide (VBTLP) was investigated using streptozotocin (STZ)-induced diabetic mice and dimethylbiguanide as the positive control. The results showed that after mice were administered VBTLP by gavage for six months, the serum insulin levels of mice in the high-dose VBTLP group was increased by 4.38%, the pancreatic β-cell function index increased by 83.40%, and the insulin secretion index increased by 63.83%, when compared with the control group. The liver antioxidant capacity of mice was significantly enhanced as well, wherein activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were increased by 2.49%, 1.74%, and 6.04%, respectively, and malondialdehyde (MDA) level was decreased by 6.12%. Based on mouse pancreatic tissue sections, VBTLP was speculated to have significant repair activity on pancreatic beta cell structure. According to the results of this study, we speculate that the hypoglycemic activity of VBTLP in STZ-induced diabetic mice results from stimulating insulin secretion, repairing the damaged pancreatic beta cells, and enhancing antioxidant capacity.

教育部留学回国人员科研启动基金资助项目；江苏省自然科学基金（BK2010146）；无锡市科技发展资金（CLE01N1312）