褪黑素对阿尔茨海默病模型大鼠学习记忆能力及海马CA3区神经元的保护作用  

Protection of melatonin on learning and memory and neurons in the hippocampal CA3 area of Alzheimer's disease model rats

作　　者：朱俊德[1] 肖朝伦[1] 余资江[1] 余彦[1] 龚明 

机构地区：[1]贵阳医学院人体解剖学教研室,贵阳550004 [2]贵州益佰制药股份有限公司药物研究所,贵阳550008

出　　处：《解剖学报》2011年第4期441-445,共5页Acta Anatomica Sinica

基　　金：贵州省教育厅自然科学研究资助项目[黔教科(2009)0139号];贵阳市科技局科技计划资助项目(2008筑科计合同字第15-21号);贵阳市科技局社会发展攻关资助项目(2010黔科农合同字第1-社-11号);贵阳医学院基金资助项目[合同字第(2009)31号]

摘　　要：目的观察褪黑素(MT)对阿尔茨海默病(AD)模型大鼠学习记忆及海马CA3区神经元的保护作用。方法随机将60只雄性Wistar大鼠分为正常对照组、AD模型组与MT治疗组。采用右侧海马CA1区注射β-淀粉样蛋白1～40(Aβ1～40)构建AD动物模型,MT治疗组以MT(10mg/kg.d)腹腔注射,正常对照组与AD模型组同时注射等体积生理盐水。给药7d后Y型迷宫检测大鼠学习记忆能力;比色法测定海马CA3区乙酰胆碱酯酶(AChE)与胆碱乙酰转移酶(ChAT)的活力;然后进行尼氏染色、Caspase-3与胶质纤维酸性蛋白(GFAP)免疫组织化学染色,光镜下观察3组大鼠海马CA3区神经元的数量与星形胶质细胞的形态变化并进行定量分析;电镜下观察各组海马CA3区神经元超微结构变化。结果与AD模型组相比,MT治疗组大鼠的学习记忆能力较AD模型组明显改善,ChAT活力显著增高(P<0.05)。光镜下,MT治疗组大鼠海马CA3区Caspase-3和GFAP阳性神经元的数量与GFAP阳性神经元的平均吸光度值均较AD模型组减少(P<0.05)。电镜下,正常对照组海马CA3区神经元结构清晰,胞核形态规则,核膜光滑、完整,核内染色质分布均匀,胞质电子密度中等,细胞器丰富;AD模型组海马CA3区神经元胞核皱缩,核周间隙增宽、核内异染色质聚集呈凋亡样改变,胞质内可见大量细胞器崩解;MT治疗组海马CA3区神经元细胞核形态规则,细胞器丰富,部分线粒体肿胀。结论 MT能改善AD模型大鼠的学习记忆能力、减轻脑组织的病理损伤,提示MT具有神经保护作用。Objective To study the behavior abilities and morphological changes of neurons in the hippocampal CA3 area of Alzheimer＇s disease （AD） model rats induced by β-amyloid protein （Aβ）1-40 and observe the effect of melatonin on the AD model rats. Methods A total of 60 Wistar rats were randomly divided into the normal control group,the AD model group and the Melatonin treat group. The AD model rats were established by microinjection of Aβ1-40 solution into right hippocampal CA1 area. Melatonin （10mg/kg · d） was injected into the abdominal cavity in the melatonin treat group for seven days, and an identical volume saline was given for the AD model group and the normal control group. The learning and memory abilities were detected by Y-maze after seven days. Then, the colorimetric method was used to detect the choline acetyltransferase （CHAT） and acetylcholinesterase （ACHE） activity. Caspase-3 and glial fibrillary acidic protein （GFAP） immunopositive cells in the hippocampal CA3 area were observed under a light microscope, and quantitative analysis was performed by cell morphometric technique. The uhra-microstructures of the neurons were observed by transmission electron microscopy （TEM）. Results Compared with the AD model group, the learning and memory abilities of the melatonin treat group were obviously improved and the ChAT activity was significantly increased （ P 〈 0.05 ） , but the quantity of Caspase-3 and GFAP immunopositive neurons were decreased （ P 〈 0. 05 ）. The average absorbance of GFAP-positive cells was significantly decreased （ P 〈 0.05 ）. Under TEM, the neurons in the hippocampal CA3 area of the normal control group had moderately electron density, regular nucleus and perinuclear membrane, chromoplasm distributed evenly and abundant cell organelles, but the neurons of the AD model groups were showed shrinkage nucleus, widen perinuclear, aggregated allochrornacy and apoptosis changes. The neurouic pathological lesion of the melatonin treat group had less

关 键 词：阿尔茨海默病 褪黑素 海马 神经元 免疫组织化学 大鼠 

分 类 号：R745.1[医药卫生—神经病学与精神病学]