改良闭环脑深部电刺激对恒河猴颞叶癫痫的治疗作用及机理研究

Epilepsy is a paroxysmal disease of nervous system that severely threatens human's health both physically and mentally. The treatment of the epilepsy can be divided into medication and surgery, but there are still part of patients out of control,and new way of treatment are required urgently. Deep brain stimulation (DBS) has already been widely accepted as an effective way to treat intractable epilepsy. "Open-loop stimulation", which is the traditional stimulation way of DBS, means stimulating continuously under a constant mode. "Closed-loop stimulation", which is the ideal condition of DBS, means stimulating before the occurrence of seizures according to the signals received by brain electrodes. The present mode of closed-loop stimulation is taking cortex electrode as recording one, and deep brain electrode the stimulating one. This research is based on the previous macaque models of epilepsy and the study of electrical signals in deep brain to improve the present mode of closed-loop stimulation, which is to omit the cortex electrode, and take the deep brain electrode both as recording and stimulating one. And we predict the coming of seizure through the alteration of the electric signals sended by the amygdala and hippocampus(AH), and then give the responsive closed-loop stimulation right before the seizures. Meanwhile, the research establishes the traditional open-loop stimulation as a control group. We wish to evaluate and compare the efficiency of treating epilepsy between the two modes under different stimulating variables based on relevant sciences, such as behaviouristics, neuroelectro- physiology, neurotransmitters, histology, ultrastructure inspection and so on. Furthermore, we hope to optimize the stimulating variables and present novel hypothesis of the mechanism on the treatment of epilepsy through DBS in the AH. Additionally, we can offer the theoretical foundation for the clinical management of epilepsy using modified closed-loop DBS of the AH.

癫痫是一种以反复发作为特点的神经系统慢性疾病，其治疗分为药物和手术两种方法，但仍有一部分病人无法控制发作，迫切需要新的治疗手段。脑深部电刺激（DBS）治疗顽固性癫痫的有效性已得到证实，但是传统的刺激模式为"开环刺激"，即按照事先设定的模式进行持续刺激；而癫痫是一种发作性疾病，如能根据电极接收到的脑电信号，在癫痫发作到来之前给予反馈刺激，即"闭环刺激"，则是癫痫电刺激治疗的理想状态。目前的闭环刺激需要皮层电极作为记录电极，深部电极作为刺激电极，本课题在前期研究的基础上，将闭环刺激进行改良，省略皮层电极，深部电极同时作为记录电极和刺激电极，通过海马杏仁核（AH）电信号变化预测即将到来的癫痫发作，在发作前进行AH闭环刺激，以传统的开环刺激作为对照，通过行为学、电生理、神经递质、组织学及超微结构等方法，评价、比较改良AH闭环刺激治疗癫痫的疗效析探讨治疗机理，为改良AH闭环电刺激的临床应用奠定基础。

癫痫是严重威胁人类健康的常见疾病，我国有900万癫痫患者，其中1/3为难治性癫痫，而颞叶癫痫（TLE）约占难治性癫痫的半数以上。对于无法进行致痫灶切除手术的顽固性TLE患者，应用现有的治疗手段仍然无法控制其发作，迫切需要新的治疗理论和体系。脑深部电刺激（DBS）是近年发展起来的以调控神经网络为主的一种治疗功能性神经系统疾病的方法，不仅在帕金森病动物模型中有神经保护作用，它对顽固性癫痫的治疗也显示出良好的应用前景；其中海马高频电刺激（HFS）治疗癫痫的有效性已在临床研究中得到证实，但是海马电刺激对TLE是否有神经保护作用仍属未知，而且其确切的作用机制尚不清楚，需要进行深入系统研究。本课题在前期研究的基础上，应用立体定向海马海人酸注射技术建立TLE恒河猴模型（靶点坐标为:前囟后8.1mm，中线向右侧旁开12mm，深入皮层35.3mm）：打开硬膜、放置皮层电极后用微量注射器缓慢、匀速注入海人酸（注射时间10min，留针10min）；手术后观察猴的行为学改变并摄像记录。我们建立植入猴海马电刺激设备模型，通过分析行为学、电生理、神经递质、组织学、western blot及超微结构检测观察海马DBS对TLE的治疗效果。本研究分别进行western电泳分析及Nissl染色和凋亡分析，以研究海马高频刺激对海人酸诱导的恒河猴TLE癫痫模型、癫痫发作对海马神经元存活的影响，探讨海马高频刺激抵抗海人酸神经元毒性的效果和潜在机制。研究结果表明，海马脑深部电刺激能够明显的减少癫痫的发作频率、减少海马神经元的丢失、抑制细胞凋，具有保护海马神经元的作用。研究表明，海马DBS通过抑制海马凋亡相关蛋白的表达(如Bax, Caspase 3)、促进海马抑制凋亡相关蛋白的表达（如 Bcl-2）起到保护海马神经元的作用。