rTMS通过内源性大麻素系统抑制帕金森病神经炎症的作用机制研究

Parkinson’s Disease (PD) is a common neurodegenerative disease, with a high disability rate and limited effect of pharmacotherapy treatment. Previous studies have revealed that repetitive transcranial magnetic stimulation (rTMS) has a beneficial effect on the syndrome of PD, with the advantages of noninvasiveness and few side effects. However, the underlying mechanism still remains unclear. It is well demonstrated that the neuroinflammation mediated by glial cells plays a critical role in the pathogenesis of PD and the endocannabinoid system (eCBS) can regulate the severity of neuroinflammation. Recently, we found that the treatment of rTMS on PD rats significantly decreased the levels of inflammatory factors in the substantia nigra and prevented the death of neurons, with remarkably upregulated expression of cannabinoid receptor 2 (CB2R); The application of antagonist of CB2R could partially counteract the anti-inflammation effects of rTMS, suggesting that eCBS is possibly involved in the treatment of rTMS on PD. Based on the preliminary work, we will firstly examine the spatio-temporal expression profile of eCBS in the substantia nigra and striatum after rTMS treatment; Then by using the agonist and antagonist of cannabinoid receptors, we will explore the effects of rTMS on the inflammatory state of glial cells in PD rat and cell models; Finally, we will further investigate the possibly underlying signaling pathway. Our study will provide the theoretical basis to further optimize the effect of rTMS on PD.

帕金森病(PD)是常见的神经退行性疾病，致残率高，药物治疗效果有限。既往临床研究表明重复经颅磁刺激(rTMS)对PD症状具有改善效果，且具有无创、副作用小等优点，但治疗机制尚不明确。已知由胶质细胞介导的神经炎症在PD发展中扮演了重要的角色，而内源性大麻素系统(eCBS)又可调控神经炎症的严重程度。我课题组预实验发现：rTMS干预明显降低PD模型大鼠黑质炎性因子含量，减少神经元死亡，同时伴有大麻素2型受体(CB2R)表达升高；干预前给与CB2R拮抗剂可以部分抵消rTMS的抗炎效果；提示eCBS可能参与了rTMS治疗PD的过程。本项目拟在前期研究基础上，首先检测rTMS干预对黑质及纹状体eCBS时空表达的影响；进而借助大麻素受体激动剂及拮抗剂，在PD动物模型及细胞模型中研究rTMS对胶质细胞炎性状态的作用；最后探索可能的下游信号通路。本项目的完成将为进一步优化rTMS治疗PD效果提供理论基础。

中脑黑质区域星形胶质细胞过度活化及相关炎性因子高表达是帕金森病(PD)发生发展的关键机制之一。重复经颅磁刺激(rTMS)是一项治疗PD很有前景的无创神经调控技术，既往研究表明可以减轻神经炎症。但两种rTMS常用治疗参数高频(HF)和低频(LF)，哪一种对PD的治疗效果及抗炎效果更佳，以及作用机制目前尚不清楚。. 本项目首先比较了HF、LF、sham rTMS对6-羟多巴胺(6-OHDA)模型大鼠多巴胺神经元存活、运动功能改善、抑制星形胶质细胞过度活化及降低炎性因子表达的作用。进一步探索了内源性大麻素(eCB)系统在rTMS抑制星形胶质细胞过度活化中的作用机制。研究发现：①与LF和sham rTMS相比，HF rTMS连续刺激6-OHDA大鼠4周具有更强的抗炎和神经保护作用，而治疗2周时，还尚未体现出HF rTMS更优的治疗效果；②在6-OHDA或LPS损伤PD模型大鼠黑质中，过度活化的星形胶质细胞高表达内源性大麻素Ⅱ型受体(CB2R)，而Ⅰ型受体(CB1R)的表达无明显变化。此外，黑质区域内源性大麻素AEA和2-AG也有所增加。HF rTMS可显著抑制星形胶质细胞过度活化，同时CB2R、AEA和2-AG的表达也降低，而LF rTMS则不能。③6-OHDA可以激活C6星形胶质细胞，伴有CB2R高表达及Erk1/2的抑制，而HF rTMS可以降低C6细胞GFAP、CB2R的表达、伴有Erk1/2信号通路激活；④CB2R的选择性激动作用能够逆转上述HF rTMS的作用，而CB2R的选择性拮抗则维持了这些作用。综上，本项目首次证实了HF较LF rTMS具有更佳的治疗效果和抗炎作用，且具有作用时间依赖性；eCB/CB2R在HF rTMS抑制神经炎症保护神经元中发挥关键作用。本项目为临床上进一步应用rTMS治疗PD提供了理论依据，同时也为开发针对eCB相关药物以提升rTMS治疗PD效果提供了潜在靶点。