经颅磁刺激对中枢神经系统胶质细胞的影响及其研究进展

Effects and research progress of transcranial magnetic stimulation on glial cells in the central nervous system

经颅磁刺激通过非侵袭性地刺激神经元,产生局部磁场,进而诱导大脑产生局部电流,最终改变大脑皮质的电生理活动。经颅磁刺激有多种模式,且每种模式产生的影响也不同。经颅磁刺激能影响神经元兴奋性,且目前已经运用于疾病的诊断和治疗。成人大脑中的大多数细胞由胶质细胞组成,在数量和多样性上远远超过神经元。主要分为五大类,成人神经干细胞:产生学习和记忆所需的新神经元;星形胶质细胞:执行一系列不同的功能,包括神经递质摄取和缓冲细胞外钾离子浓度;少突胶质细胞:生成髓鞘以及为轴突提供营养支持;少突胶质细胞前体细胞:增殖并形成新的少突胶质细胞;小胶质细胞:是常驻的免疫细胞。每种类型的神经胶质细胞都有直接或间接应答电活动的能力:经颅磁刺激可以促进成人神经干细胞/祖细胞增殖,但对细胞存活和分化的影响还不明确;资料显示经颅磁刺激通过刺激星形胶质细胞,进而对突触的形成、成熟、修剪以及树突棘的形状产生影响;经颅磁刺激对星形胶质细胞和小胶质细胞的研究资料有限;虽然经颅磁刺激少突胶质细胞能动态调节神经传导速度,但其对少突胶质细胞的作用也缺乏完整资料。然而胶质细胞又在中枢神经系统起着至关重要的作用,所以经颅磁刺激对神经胶质细胞的影响无疑是一个值得仔细探查的领域。

Transcranial magnetic stimulation(TMS)non-invasively stimulates neurons by generating a localised magnetic field,which could induce an electrical current in the brain.TMS can regulate brain activity in different patterns.TMS has been applied to the diagnosis and treatment of different diseases because of its effects on neurons and glial cells.Glia comprise the majority of cells in the adult brain,far exceeding neurons in number and diversity.Glial cells can be divided into five types:adult neural stem cells,which generate new neurons that are required for learning and memory;astrocytes,which perform a diverse range of functions,including neurotransmitter uptake and the buffering of extracellular potassium ion concentration;oligodendrocytes,which support axons through myelin production and favour trophic growth;oligodendrocyte progenitor cells,which can promote the proliferation and generation of new oligodendrocytes;and microglia,which are the resident immune cells of the brain.Each type of glial cell could be influenced by electrical activity directly or indirectly,making them possible cellular effectors of TMS.TMS can promote the proliferation of adult neural stem cells/progenitor,but its influence on cell survival and differentiation is unclear.TMS can stimulate astrocytes and then influence the formation,maturation,synaptic pruning and shape of dendritic spines.The research data of TMS on astrocytes and microglia are limited.The TMS of oligodendrocytes can dynamically regulate nerve conduction velocity.Data relating to the response of oligodendrocyte-lineage cells to this treatment are lacking.However,glial cells play a vital role in the central nervous system.Thus,the influence of TMS on glial cells warrants careful examination.