茶多酚对血管性痴呆大鼠学习记忆功能的影响

Effects of Tea polyphenol on learning and memory function in vascular dementia rats

目的探讨茶多酚(TP)对血管性痴呆(VD)大鼠学习记忆功能的影响。方法 40只SD大鼠随机分为假手术组、模型组、TP 0.1 g/kg组、TP 0.2 g/kg组,给药组每天1 ml/100 g TP灌胃,假手术组和模型组给予等量蒸馏水。预先给药30 d后,采用腹腔注射硝普钠合并双侧颈动脉反复缺血再灌注法制备VD模型,假手术组仅分离不夹闭,各组继续给药。1周进行Nissal染色,观察并计算大鼠海马CA1区的神经元形态变化及阳性细胞数量;4周利用跳台实验检测大鼠的学习记忆能力;比色法测定脑组织中乙酰胆碱酯酶(AChE)活性及乙酰胆碱(ACh)含量;ELISA法检测Aβ_(1-42)水平。结果尼氏染色显示0.1 g/kgTP组、0.2 g/kg TP组神经元数量较模型组明显增多、细胞形态趋于完整,核仁分明,尼氏体丰富;0.2 g/kg TP组阳性细胞数明显增多(P<0.01)。0.1 g/kg TP组、0.2 g/kg TP组跳台潜伏期分别较模型组明显延长(分别为P<0.05,P<0.01),错误次数明显减少(分别为P<0.05,P<0.01)。0.1 g/kg TP组、0.2 g/kg TP组AChE活性逐渐降低(分别为P<0.05,P<0.01),且具有剂量依赖性。0.2 g/kg TP组Ach含量明显增多(P<0.01)。0.1 g/kg TP组、0.2 g/kg TP组Aβ_(1-42)表达较模型组降低(P<0.05)。结论 TP能够改善VD大鼠的学习记忆功能,其机制可能与保护神经元、降低AChE活性、增加Ach含量、减少Aβ_(1-42)表达有关。

Objective To investigate the effects of Tea polyphenol（TP）on learning and memory function in vascular dementia（VD）rats. Methods Forty SD rats were randomly divided into sham operation group,model group,0.1 g/kg TP group,0.2 g/kg TP group. The drug groups were given by gavage once a day each rat. The sham operation group and the model group were given equal amounts of distilled water. VD rats were established by intercepting both common carotid arteries and injecting sodium nitroprusside after 30 days. Brain tissue was stained by Nissl staining,observing the shape and number of neurons and Nissl bodies,and then judge the damaged nerve after a week. The influence of TP on learning and memory function was observed by step down test. The activity of acetylcholinesterase（AchE）and acetylcholine（Ach）in brain tissues were investigated by colorimetry;ELISA method was used to detect the level of Aβ1-42 Results Compared with the model group,the neuronal integrity of hippocampus in 0.1 g/kg TP group,0.2 g/kg TP group was improved obviously in Nissl staining,and the Nissl bodies were abundant and clearly visible. The number of positive cells in 0.2 g/kg TP group were increased significantly（P〈0.01）. In the step-down test,compared with the model group,the latency of 0.1 g/kg TP group,0.2 g/kg TP group was prolonged（P〈0.05,P〈0.01,respectively）;Error Times were decreased（P〈0.05,P〈0.01,respectively）. The activity of AchE was decreased in 0.1 g/kg TP group,0.2 g/kg TP group（P〈0.05,P〈0.01,respectively）and the content of Ach in brain tissues were increased in TP 0.2 g/kg group（P〈0.01）. Compared with the model group,Aβ1-42was lower in TP 0.1 g/kg group,0.2 g/kg TP group（P〈0.05）. Conclusion TP can improve the learning and memory function in VD rats through protecting neurons and regulating the expression of Ach and Aβ1-42.