摘要：

研究背景 脑源性神经营养因子（BDNF）在阿尔茨海默病（AD）发病机制中发挥重要作用，微小RNA-132（miRNA-132）在神经元呈高表达，可以通过调控靶基因表达参与BDNF 介导的神经发育过程。本研究旨在探讨阿尔茨海默病神经元模型中miRNA-132 与BDNF的调控关系和神经保护作用。方法 体外培养海马神经元72 h 后慢病毒转染miRNA-132，并于体外培养第7 天以β-淀粉样蛋白（Aβ）处理制备阿尔茨海默病神经元模型；实时荧光定量聚合酶链反应观察对照组与AD 组miRNA-132表达差异以及不同处理组BDNF mRNA 表达变化，噻唑蓝法观察不同处理方式对细胞活性的影响。结果 （1）AD 组海马神经元miRNA-132（t = 13.888，P = 0.000）和BDNF RNA（t = -12.274，P = 0.000）表达水平均低于对照组。（2）原代培养的海马神经元经慢病毒转染后倒置相差荧光显微镜可见绿色荧光蛋白，对照组（t = 16.135，P = 0.000）和AD 组（t = 8.656，P = 0.000）转染过表达miRNA-132 后均能上调BDNF mRNA 表达。（3）AD 组海马神经元活性降低（t = -6.023，P = 0.000），AD 组转染miRNA-132 后神经元活性增强（t = 3.385，P = 0.007），予以外源性BDNF 共培养后神经元活性明显改善（t = 3.672，P = 0.004）。结论 阿尔茨海默病神经元模型miRNA-132 和BDNF 表达水平均下降，miRNA-132 可上调BDNF 表达，提示miRNA-132 和BDNF 对阿尔茨海默病神经元模型具有神经保护作用，有望为阿尔茨海默病诊断与治疗提供新的视角。

关键词: 微RNAs, 脑源性神经营养因子, 淀粉样β蛋白, 神经元, 聚合酶链反应, 细胞, 培养的

Abstract:

Background  Brain-derived neurotrophic factor (BDNF) plays a crucial role in the pathogenesis of Alzheimer's disease (AD). MicroRNA (miRNA)-132, which is widely expressed in neurons, is involved in BDNF-mediated neural development by regulating the expression of target gene. This study aims to investigate the effect of miRNA-132 on BDNF and its neuroprotective effect.  Methods  The hippocampal neurons were transfected by miRNA-132 after 72 h in vitro, then exposed to amyloid β-protein (Aβ) on the 7th day to build AD models. The difference of miRNA-132 expression between AD group and control group was detected by real-time fluorescent quantitative polymerase chain reaction (PCR). The alterations of BDNF mRNA were observed in the neurons of different groups. Finally, the cell viability was observed by methyl thiazolyl tetrazolium (MTT) assay in AD neurons transfected with miRNA-132 or incubated with BDNF. Results 1) MiRNA-132 was significantly decreased (t = 13.888, P = 0.000), and the expression of BDNF mRNA was also reduced in AD group (t = -12.274, P = 0.000). 2) Green fluorescence was clearly visible by inverted phase-contrast fluorescence microscopy after transfected with miRNA-132. BDNF mRNA was upregulated when miRNA-132 overexpression both in control group (t = 16.135, P = 0.000) and AD group (t = 8.656, P = 0.000). 3) Cell viability was obviously decreased in neurons exposed to Aβ (t = -6.023, P = 0.000), which was improved when transfected with miRNA-132 (t = 3.385, P = 0.007) or incubated with BDNF (t = 3.672, P = 0.004).  Conclusions  The expression of miRNA-132 and BDNF was reduced in neuronal AD model. MiRNA-132 played an important role on neuroprotection against A β-induced neuronal damage via upregulation of BDNF. It could be expected to provide new perspective for the diagnosis and treatment of AD.

Key words: MicroRNAs, Brain-derived neurotrophic factor, Amyloid beta-protein, Neurons, Polymerase chain reaction, Cells, cultured