天麻提取物对血管性痴呆大鼠学习记忆及海马氧化损伤的作用

Effects of extract from Gastrodia elata Blume on learning-memory ability and oxidative damage to hippocampus with vascular dementia in rats

目的观察天麻提取物对血管性痴呆(vascular dementia,VD)大鼠模型学习记忆能力及海马氧化损伤的影响。方法采用双侧颈总动脉永久性结扎法,造成慢性脑灌注不足所致SD大鼠VD模型。术后分别灌胃给予天麻提取物高剂量7.29 g/(kg.d)、低剂量0.81 g/(kg.d)、尼莫地平30 mg/(kg.d),假手术组与模型组给予等体积的生理盐水,给药3周后,用Morris水迷宫检测各组大鼠逃避潜伏期和搜索距离;同时检测海马组织内丙二醛(MDA)量、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-PX)活性。结果与模型组相比,天麻提取物高剂量能明显缩短逃避潜伏期和搜索距离(P<0.05),使大鼠海马组织内MDA量降低、SOD和GSH-PX活性及SOD/MDA比值升高(P<0.05)。结论天麻提取物具有改善血管性痴呆模型大鼠的学习记忆能力,其机制可能与清除自由基、减轻海马区的氧化损伤有关。

AIM To evaluate the effects of extract from Gastrodia elata Blume on learning-memory ability and the oxidative damage to hippocampus in rats with vascular dementia.METHODS The experimental vascular dementia model was established by chronic cerebral ischemia induced by permanent occlusion of bilateral carotid arteries.Sprague-Dawley rats were randomly divided into sham-operation group,model group,positive control（nimodipine） group and intervention group（fourteen rats each group）.The intervention group were administered with extract from Gastrodia elata Blume at a dose of 7.29 g/kg,and 0.81 g/kg,respectively,the positive control group were administered with nimodipine 30mg/kg,sham-operation group and model group were administered with normal saline.After three weeks,animals of all groups were tested for the Morris water maze,the escape latency and path traveled to reach the platform were detected,and then the malonaldehyde（MDA） content,the activity of superoxide dismutase（SOD） and glutathione peroxidase（GSH-PX）in hippocampus were measured.RESULTS The rats administered with extract from Gastrodia elata Blume at 7.29 g/kg demonstrated better learning and memory ability than those of model group（P〈0.05） in water maze test by showing a significantly shorter latency period and path length.Moreover,it could markly increase the activity of SOD and GSH-PX while decrease the MDA content in hippocampus（P〈0.05）.CONCLUSION These results suggest that extract from Gastrodia elata Blume can improve the learning-memory ability in rats with experimental vascular dementia,one of the mechanisms may be related to scavenging free radicals and reducing oxidative damage to hippocampus of rats.