经rTMS易化的FES对脑梗死使用依赖可塑性cAMP/PKA-MAPK-BDNF-CREB通路的研究

我们以往研究发现功能性电刺激（FES）通过增强“使用依赖可塑性”改善脑卒中后运动及认知功能，但疗效有限，治疗周期较长，主要考虑与脑梗死后半球间抑制增强有关。低频重复经颅磁刺激（rTMS）通过降低损伤对侧神经元兴奋性，继而降低半球间的抑制，增加梗死周边区运动皮层神经元兴奋性，增强随后的偏瘫肢体运动训练时神经元的募集。预实验结果显示给予脑梗死大鼠损伤对侧运动皮层低频rTMS再予FES治疗，与单独FES相比，梗死周边区运动皮层pCREB及pCaMKⅡ含量显著升高。因此我们假设rTMS预刺激可以提高FES的敏感性，缩短FES治疗周期，其机制可能通过进一步上调梗死周边区及海马突触可塑性cAMP/PKA-MAPK-BDNF-CREB通路。本研究建立脑梗死模型，在FES前予rTMS，后评定偏瘫肢体运动、认知功能及梗死周边运动皮层及海马可塑性变化，以阐明rTMS是否提高FES对脑卒中的治疗效果及相关机制。

Our team has demonstrated that functional electrical stimulation (FES) improved the functional recovery of patients with stroke through strengthening the activity-dependent plasticity, however, the effectiveness of FES is limited and slow with long treatment period. This phenomenon is thought to attribute to an increased interhemispheric inhibition of the affected motor cortex (affM1) by the disinhibited intact motor cortex (intM1), and then affM1 showed low excitability. Recently, noninvasive brain stimulation, in particular, low-frequency repetitive transcranial magnetic stimulation (rTMS), has been employed to promote functional recovery by suppressing the intM1 and thus reducing interhemispheric inhibition and promoting use-dependent motor plasticity. Our previous study on the stroke rats found priming FES with inhibitory rTMS could increase pCREB and pCaMKⅡ at the area of the affected motor cortex. Therefore, we hypothesized that rTMS might increase the sensitivity of FES and further shorten the treatment period of FES to improve the functional recovery of rats with ischemic stroke via the pathway of cAMP/PKA-MAPK-BDNF-CREB. In this study, we will first establish the stroke model in rats. Then rTMS (conductive shielding plate to improve accuracy of rTMS position) will be used prior to FES. After the intevention, the rats will be assessed in aspects of mNSS, NOR, Mirros maze and barnes maze. The calcium concentration of intracellular will be measured using confocal laser scanning microscopy and the changes of LTP will also be examined as well as the changes of protein expression associated cAMP/PKA-MAPK-BDNF-CREB signaling pathways in the maintain phase of LTP. The results of this study are expected to identify whether rTMS preceding FES on the affected limb of rats with ischemiac stroke can improve the efficacy of FES, shorten treatment duration and enhance neurorabilitation post stroke.