桑枝低聚糖对高脂饮食/链脲佐菌素诱导的糖尿病小鼠的降血糖活性

本研究以桑枝低聚糖为原料，通过体内实验评价其对糖尿病小鼠降血糖功效。通过高脂饲料结合注射链脲佐菌素建立糖尿病小鼠模型，采用低剂量（200.00 mg/（kg·bw））、中剂量（400.00 mg/（kg·bw））、高剂量（800.00 mg/（kg·bw））桑枝低聚糖对模型小鼠灌胃干预。定期测定小鼠体质量、空腹血糖值，40 d后测定小鼠口服糖耐量、胰岛素水平、氧化应激水平、肾脏相关酶、肠道菌群组成的变化，观察小鼠结肠的病理形态，评估桑枝低聚糖对糖尿病小鼠血糖等生化指标的影响，及其对肠道菌群的作用。结果表明，与模型组相较，桑枝低聚糖延缓了糖尿病小鼠的体重下降，对空腹血糖和糖耐量均有一定程度降低。经桑枝低聚糖治疗后，糖尿病小鼠的胰岛素水平显著降低（P<0.05），SOD、GSH水平显著提高（P<0.05），MDA含量显著降低（P<0.05），CRE、BUN水平有效降低。通过对糖尿病小鼠的肠道菌群进行16S rDNA分析，发现桑枝低聚糖有效增加了肠道微生物的丰富度，在门的水平上，减少厚壁菌门丰度，增加拟杆菌门丰度；在科的水平上，提高乳杆菌科的比例；在属的水平上，提高乳酸杆菌属的比例，并且降低毛螺菌属的比例。证实桑枝低聚糖能够通过改善胰岛素抵抗、改善氧化应激水平，调节肠道菌群等途径降低糖尿病小鼠血糖、缓解糖尿病小鼠消瘦的状况，修复结肠与肾脏损伤，从而起到降血糖作用，在低剂量（200.00 mg/（kg·bw））下就能够发挥较好的降血糖功效，作用效果与剂量无明显线性关系。

Hypoglycemic Activity of Ramulus mori Oligosaccharides on High-fat Diet/Streptozotocin-Induced Diabetic Mice

Ramulus mori oligosaccharides were used as the raw material to evaluate its hypoglycemic effect on high-fat diet/streptozotocin-induced diabetic mice through in vivo experiments. The diabetic mice model was established by high-fat diet combined with injection of streptozotocin, and it was given low-dose (200.00 mg/(kg·bw)), medium-dose (400.00 mg/(kg·bw)) and high-dose (800.00 mg/(kg·bw)) of Ramulus mori oligosaccharides by gavage intervention. In order to evaluate the effects of Ramulus mori oligosaccharides on biochemical indicators and intestinal flora in diabetic mice, the body weight and fasting blood glucose value of the mice were regularly measured. After 40 days, the oral glucose tolerance, insulin level, oxidative stress level, intestinal flora composition, kidney-related enzymes of the mice were measured, and the pathological morphology of the mice colon was observed. The results showed that Ramulus mori oligosaccharides alleviated the weight loss of the diabetic mice, decreased fasting blood glucose and glucose tolerance to a certain extent compared with the model group. After treatment with Ramulus mori oligosaccharides, the insulin level of diabetic mice was significantly decreased (P<0.05), the SOD and GSH activity were significantly increased (P<0.05), the MDA content was significantly decreased (P<0.05), and the CRE and BUN levels were effective reduced. By 16S rDNA analysis of the intestinal flora of the diabetic mice, it was found that Ramulus mori oligosaccharides effectively increased the abundance of intestinal microorganisms. It reduced the abundance of Firmicutes and increased the abundance of Bacteroidetes at the phylum level, increased the proportion of Lactobacillus at the family level, increased the proportion of Lactobacillus and decreases the proportion of Lachnospira at the genus level. It was confirmed that Ramulus mori oligosaccharides could reduce blood sugar, relieve weight loss in the diabetic mice, and repair colon and kidney damage by improving insulin resistance, improving oxidative stress levels, and regulating intestinal flora, thereby reducing blood glucose. It could exert a good hypoglycemic effect at a low dose (200.00 mg/(kg·bw)), but there was no obvious linear relationship between the hypoglycemic effect and the dose.