比较 50Hz 低频和 10kHz 高频胸段脊髓刺激对心肌梗死猪模型脊髓神经网络的记忆效应。
Comparing the Memory Effects of 50-Hz Low-Frequency and 10-kHz High-Frequency Thoracic Spinal Cord Stimulation on Spinal Neural Network in a Myocardial Infarction Porcine Model.
机构信息
Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Medicine, Division of Cardiology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
出版信息
Neuromodulation. 2024 Oct;27(7):1177-1186. doi: 10.1016/j.neurom.2024.06.002. Epub 2024 Jul 31.
OBJECTIVE
This study evaluated the effects of cessation of both conventional low-frequency (50 Hz) and high-frequency (10 kHz) spinal cord stimulation (SCS) on the cardiospinal neural network activity in pigs with myocardial infarction (MI). The objective is to provide an insight into the memory effect of SCS.
MATERIALS AND METHODS
In nine Yorkshire pigs, chronic MI was created by delivering microspheres to the left circumflex coronary artery. Five weeks after MI, anesthetized pigs underwent sternotomy to expose the heart for performing acute ischemia intervention, and laminectomy to expose the T1-T4 spinal regions for extracellular in vivo neural recording and SCS. Cardiac ischemic-sensitive neurons were identified by selective responsiveness to left anterior descending (LAD) coronary artery occlusion. SCS episodes were delivered in a random order between low- (50 Hz) and high- (10 kHz) frequency, for 1 minute, at 90% of the motor threshold current. Neural firing and synchrony of ischemic-sensitive spinal neurons were evaluated before vs after SCS.
RESULTS
Using a 64-channel microelectrode array, 2711 spinal neurons were recorded extracellularly. LAD ischemia excited 228 neurons that were labeled as ischemic-responsive neurons. The cessation of 50-Hz SCS caused a higher activation than did inhibition of ischemic-responsive neurons (41 activated vs 19 inhibited), whereas the cessation of 10-kHz SCS caused an opposite response with higher inhibition (11 activated vs 28 inhibited, p < 0.01 vs 50 Hz). Termination of low-frequency SCS caused an increase in ischemic-responsive neuronal firing rate compared with high-frequency SCS (50 Hz: 0.39 Hz ± 0.16 Hz, 10 kHz: -0.11 Hz ± 0.057 Hz, p < 0.01). In addition, SCS delivered at 50 Hz increased the number of synchronized pairs of neurons by 205 pairs, whereas high-frequency SCS decreased the number of synchronized pairs by 345 pairs (p < 0.01).
CONCLUSIONS
High-frequency (10 kHz) stimulation provides persistent suppression of the ischemia-sensitive neurons after termination of SCS. In contrast, the spinal neural network reverted to excitatory state after termination of low-frequency (50 Hz) stimulation.
目的
本研究评估了停止常规低频（50 Hz）和高频（10 kHz）脊髓刺激（SCS）对心肌梗死（MI）猪心脑血管神经网络活动的影响。目的是深入了解 SCS 的记忆效应。
材料和方法
在 9 头约克夏猪中，通过向左回旋冠状动脉输送微球来创建慢性 MI。MI 后 5 周，麻醉猪进行开胸手术暴露心脏以进行急性缺血干预，并进行椎板切除术以暴露 T1-T4 脊髓区域进行细胞外体内神经记录和 SCS。通过对左前降支（LAD）冠状动脉闭塞的选择性反应性来鉴定心脏缺血敏感神经元。SCS 发作以随机顺序在低（50 Hz）和高（10 kHz）频率之间进行，持续 1 分钟，达到运动阈值电流的 90%。在 SCS 前后评估缺血敏感脊髓神经元的放电和同步性。
结果
使用 64 通道微电极阵列，记录了 2711 个脊髓神经元。LAD 缺血激发了 228 个被标记为缺血反应神经元的神经元。停止 50-Hz SCS 引起的激活高于抑制缺血反应神经元（41 个激活与 19 个抑制），而停止 10-kHz SCS 引起的相反反应具有更高的抑制（11 个激活与 28 个抑制，p <0.01 与 50 Hz 相比）。低频 SCS 的终止导致与高频 SCS 相比，缺血反应神经元的放电率增加（50 Hz：0.39 Hz ± 0.16 Hz，10 kHz：-0.11 Hz ± 0.057 Hz，p <0.01）。此外，50 Hz 的 SCS 增加了 205 对同步神经元对，而高频 SCS 减少了 345 对同步神经元对（p <0.01）。
结论
高频（10 kHz）刺激在 SCS 终止后提供对缺血敏感神经元的持续抑制。相比之下，低频（50 Hz）刺激终止后，脊髓神经网络恢复兴奋状态。
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