地黄寡糖对糖尿病大鼠空间学习记忆的影响

目的研究地黄寡糖对糖尿病大鼠空间学习记忆的影响及其机制。方法采用链脲佐菌素制备大鼠糖尿病模型,随机分为正常对照组、正常用药组（500 mg/kg）、糖尿病模型组、低剂量和高剂量地黄寡糖治疗组（100 mg/kg、500 mg/kg）;定期检测动物体重及血糖;11周后进行Morris水迷宫实验测定大鼠学习记忆能力,随后取海马组织,测定谷氨酸和γ-氨基丁酸含量。结果模型组、低剂量治疗组和高剂量治疗组与对照组相比,体重都明显减轻,血糖也明显升高,海马组织中谷氨酸水平分别提高了30.8%（P〈0.05）,32.5%（P〈0.01）和29.9%;同时模型组比对照组逃避潜伏期明显延长,在原平台象限游泳时间占总游泳时间的百分比明显降低;低剂量治疗组和高剂量治疗组与模型组相比,逃避潜伏期明显缩短,在原平台象限的游泳时间占总游泳时间的百分比明显增加,并且γ-氨基丁酸含量分别高出模型组13.7%和14.8%;正常用药组和对照组相比,γ-氨基丁酸含量明显升高。结论糖尿病大鼠空间学习记忆能力下降,地黄寡糖对其学习记忆能力具有一定的改善作用,这可能与其提高海马组织中γ-氨基丁酸的相对水平,防止高水平谷氨酸引起的神经元过度兴奋有关。

Effects of rehmannia glutinosa oligosaccharides on diabetes-induced spatial learning and memory impairment in rats

【Objective】To investigate the effects of Rehmannia glutinosa oligosaccharides on learning and memory abilities and its mechanism.【Methods】Experimental diabetes was induced by treatment with streptozotocin.Rats were randomly divided into 5 groups： the control group,Rehmannia glutinosa oligosaccharides-treated normal group（500 mg/kg）,diabetic model group,low dose of Rehmannia glutinosa oligosaccharides-treated diabetic group（100 mg/kg） and high dose treated diabetic group（500 mg/kg）.The body weight and serum glucose were measured.After 11 weeks of streptozotocin injection,all groups were tested in Morris water maze,to detect spatial learning and memory abilities.After that,all of the rats were sacrificed by decapitation,and then both hippocampi were harvested.The contents of glutamate and gama-aminobutyric were determined by High Performance Liquid Chromatography.【Results】Compared to the control group,body weight of rats in diabetic model group,low dose treated diabetic group and high dose treated diabetic group decreased significantly,while their blood glucose increased significantly,and glucose content increased by 30.8%（P0.05）,32.5%（P0.01） or 29.9% respectively.The latency swum to reach the platform increased significantly in diabetic model group as compared to the control group,while the percentage of time spent in target quadrant decreased significantly.Compared to the diabetic model group,the latency swum to reach the platform decreased significantly and the percentage of time spent in target quadrant increased significantly both in low dose treated diabetic group and high dose treated diabetic group,while the content of gama-aminobutyric increased by 13.7% or 14.8% respectively,compared with the diabetic model group.The content of gama-aminobutyric in Rehmannia glutinosa oligosaccharides-treated normal group increased significantly as compared to the control group.【Conclusion】Rehmannia glutinosa oligosaccharides treatment may prevent the decrease in learning and memory ability of streptozotocin-diabetic rats.It is probably associated with increased content of gama-aminobutyric in hippocampus,inhibiting neuronal hyperexcitability induced by glutamate.