Chen Yu, Mao Lin, Zhou Qinxiang, Bai Dingqun, Kong Yuhan
Department of Rehabilitation, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China; Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China; Department of Respiratory and Critical Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan Province 610000, China.
Department of Rehabilitation, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China; Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
Brain Res Bull. 2025 Jan;220:111164. doi: 10.1016/j.brainresbull.2024.111164. Epub 2024 Dec 9.
Transcranial direct current stimulation (tDCS) has an impact on improving cognitive and motor dysfunction induced by ischemia-reperfusion injury. However, to use this technology more rationally in clinical practice, a deepened understanding of the molecular mechanisms behind its therapeutic effects is needed. This study explored the role of the brain-derived neurotrophic factor(BDNF) and its associated receptor tropomyosin-receptor kinase B(TrkB) while deciphering the underlying mechanisms in transcranial direct current therapy to treat ischemic stroke.
A middle cerebral artery occlusion-reperfusion(MCAO/R) model was established in rats to observe tDCS effects on brain damage. Behavioral tests, the modified neurologic severity score(mNSS), and the Hoffman reflex / the M wave(H/M) ratio helped assess motor function and neurologic deficits. HE and Nissl staining helped observe the morphological changes and count of nerve cells. We tested the expression of growth-associated protein-43(Gap-43) and microtubule-associated protein-2(Map-2), K-Cl co-transporter 2(KCC2), γ-aminobutyric acid(GABA), and key BDNF-TrkB downstream signaling, the phospholipase C gamma(PLCγ) / CaMK IV / cAMP response element binding protein(CREB), and extracellular signal-regulated protein kinase(ERK1/2) / ribosomal S6 kinase(RSK) using western blotting. Moreover, BDNF was analyzed in plasma using the enzyme-linked immunosorbent assay (ELISA) to investigate the tDCS effect on human BDNF expression levels. Finally, a BDNF receptor antagonist, ANA-12, was administered to explore the tDCS mechanism mediating BDNF-TrkB signaling.
After tDCS treatment, the mNSS was improved, and the motor function was restored. Moreover, tDCS decreased cell swelling after MCAO/R and enhanced the number of neurons. tDCS treatment increased: (1) BDNF, Gap-43, Map-2 expression, (2) KCC2, GABA, and (3) PLCγ, CaMK IV, CREB and ERK1/2, RSK. Furthermore, ELISA results indicate that tDCS elevated human plasma BDNF protein expression. However, the therapeutic effect of tDCS was suppressed to a certain extent by adding ANA-12.
Our findings indicate that tDCS may exert a neuroprotective effect by activating the downstream key molecules of BDNF-TrkB expression, for instance, PLCγ/ CaMK IV/ CREB and ERK/ RSK pathway. Moreover, tDCS can control neuronal excitability, promote axonal regeneration, and accelerate motor function recovery in ischemia reperfusion-injured rats.
经颅直流电刺激（tDCS）对改善缺血再灌注损伤所致的认知和运动功能障碍具有一定作用。然而，为了在临床实践中更合理地应用该技术，需要深入了解其治疗效果背后的分子机制。本研究探讨了脑源性神经营养因子（BDNF）及其相关受体原肌球蛋白受体激酶B（TrkB）的作用，同时阐明经颅直流电疗法治疗缺血性脑卒中的潜在机制。
在大鼠中建立大脑中动脉闭塞-再灌注（MCAO/R）模型，以观察tDCS对脑损伤的影响。行为学测试、改良神经功能缺损评分（mNSS）以及霍夫曼反射/ M波（H/M）比值有助于评估运动功能和神经功能缺损。苏木精-伊红（HE）和尼氏染色有助于观察神经细胞的形态变化并进行计数。我们使用蛋白质免疫印迹法检测生长相关蛋白43（Gap-43）、微管相关蛋白2（Map-2）、钾氯共转运体2（KCC2）、γ-氨基丁酸（GABA）以及BDNF-TrkB下游关键信号磷脂酶Cγ（PLCγ）/钙调蛋白激酶IV（CaMK IV）/环磷酸腺苷反应元件结合蛋白（CREB）和细胞外信号调节蛋白激酶（ERK1/2）/核糖体S6激酶（RSK）的表达。此外，采用酶联免疫吸附测定（ELISA）法分析血浆中的BDNF，以研究tDCS对人BDNF表达水平的影响。最后，给予BDNF受体拮抗剂ANA-12，以探讨介导BDNF-TrkB信号传导的tDCS机制。
tDCS治疗后，mNSS评分改善，运动功能恢复。此外，tDCS减轻了MCAO/R后的细胞肿胀，并增加了神经元数量。tDCS治疗使以下各项增加：（1）BDNF、Gap-43、Map-2的表达，（2）KCC2、GABA，以及（3）PLCγ、CaMK IV、CREB和ERK1/2、RSK。此外，ELISA结果表明tDCS提高了人血浆BDNF蛋白表达。然而，加入ANA-12后，tDCS的治疗效果在一定程度上受到抑制。
我们的研究结果表明，tDCS可能通过激活BDNF-TrkB表达的下游关键分子，如PLCγ/CaMK IV/CREB和ERK/RSK信号通路，发挥神经保护作用。此外，tDCS可以控制神经元兴奋性，促进轴突再生，并加速缺血再灌注损伤大鼠的运动功能恢复。
