天麻素抑制小鼠大脑内Aβ斑块形成及其作用机制  

Effect and mechanism of gastrodin inhibiting β-amyloid plaques in brain of mice

作　　者：周楠楠[1] 朱燃[1] 赵雪梅[1] 张冀民[2] 梁平[1] 

机构地区：[1]中国医学科学院基础医学研究所北京协和医学院基础学院,北京100005 [2]美国哈佛大学医学院神经疾病研究中心,波士顿02115

出　　处：《药学学报》2016年第4期588-594,共7页Acta Pharmaceutica Sinica

基　　金：国家"十二五"科技重大专项"重大新药创制"项目(2012ZX09103301-051)

摘　　要：观察天麻素对5×FAD阿尔茨海默病(Alzheimer’s disease,AD)模型小鼠脑内Aβ纤维斑块的影响,并利用117模型细胞(过表达Aβ和β-分泌酶)研究其可能的作用机制。5×FAD小鼠随机分为天麻素(gastrodin,GAS)高剂量(200 mg·kg^(-1)·d^(-1))、中剂量(100 mg·kg^(-1)·d^(-1))及低剂量(50 mg·kg^(-1)·d^(-1)),并设置5×FAD阳性小鼠对照组及5×FAD阴性小鼠对照组。用药3个月后,用Morris水迷宫检测小鼠行为学变化,ELISA法检测小鼠脑匀浆中Aβ含量,免疫组化观察5×FAD小鼠脑内海马区及皮层区Aβ斑块。天麻素以不同的浓度(10~100μmol·L^(-1))作用于117细胞,分别检测细胞内外Aβ含量变化,分析细胞内β-分泌酶转录水平和蛋白水平的变化,以及细胞凋亡、细胞活力的变化情况。结果显示:与5×FAD阳性对照组相比,天麻素高剂量组(GAS-H)平台寻找时间缩短50.60%,在目标象限逗留时间延长2.25倍;脑匀浆中Aβ含量下降55.74%;脑内Aβ斑块在海马区减少93.28%,在皮质区减少88.88%;117细胞实验结果表明,天麻素在100μmol·L^(-1)时细胞内外Aβ含量分别降低63.1%和49.1%,且降低的效果呈浓度依赖性;天麻素在100μmol·L^(-1)时细胞β-分泌酶转录水平降低32.9%;50μmol·L^(-1)时细胞β-分泌酶蛋白表达水平降低47.9%。结果提示:天麻素可抑制5×FAD鼠脑内Aβ纤维斑块,同时可明显改善其学习记忆及认知能力。初步研究其机制,发现可能与抑制β-分泌酶的表达进而抑制Aβ及其纤维斑块的形成有关。This study was designed to investigate the effect of gastrodin（GAS） against β-amyloid plaques in 5×FAD Alzheimer＇s disease（AD） transgenic mice, and utilize 117 cell model（over-expression of Aβ and β-secretase） to explore the underlying mechanism. 5×FAD mice model were randomly divided into three groups, including GAS-high dose group（GAS-H, 200 mg·kg^（-1）·d^（-1））, GAS-middle dose group（GAS-M, 100 mg·kg^（-1）·d^（-1）） and GAS-low dose group（GAS-L, 50 mg·kg^（-1）·d^（-1））. Meanwhile, the wild type mice were used in the control group. After being treated with GAS for three months, 5×FAD mice were evaluated by Morris water maze for the learning and memory ability and by ELISA for Aβ in the cerebral homogenate. Then, Aβ plaques in the hippocampus and cortex of 5×FAD mice were observed and analyzed with immunohistochemical staining. The cell apoptosis rate and the cell viability were determined in vitro, after the cells were treated with different concentrations of GAS（10, 25, 50 and 100 μmol·L^（-1））. Furthermore, Intracelluar/extracelluar Aβ were determined by ELISA. Effects of GAS on BACE（β-secretase site APP cleaving enzyme） m RNA and protein expression were analyzed in 117 cell models by Q-PCR and Western blotting. The results suggest that GAS is able to restore the learning and memory capacity of 5×FAD mice, and reduce Aβ in the cerebral homogenate and Aβ plaques in the brain. Compared with the untreated transgenic positive group, Aβ plaques were declined in hippocampus and cortex of GAS-H group by 93.28% and 88.88%, and Aβ was reduced in the cerebral homogenate by 55.74%. In vitro study suggests a dose-dependent effect of GAS in reducing Aβ in 117 cell models. When the cells were treated with 100 μmol·L^（-1） GAS, extracelluar Aβ and intracellular Aβ of 117 cells were reduced by 63.1% and 49.1%. BACE expression was largely suppressed in m RNA by 32.9%（P〈 0.01）. At 50 μmol·L^（-1） GAS, the protein level was declined

关 键 词：阿尔茨海默病 天麻素 Β淀粉样多肽 Β-分泌酶 海马 大脑皮层 

分 类 号：R966[医药卫生—药理学]