Department of Otolaryngology, Zhongshan Hospital, Fudan University, Shanghai, China.
ENT Institute and Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.
Neural Plast. 2020 Sep 6;2020:3108490. doi: 10.1155/2020/3108490. eCollection 2020.
Cochlear implant-based electrical stimulation may be an important reason to induce the residual hearing loss after cochlear implantation. In our previous study, we found that charge-balanced biphasic electrical stimulation inhibited the neurite growth of spiral ganglion neurons (SGNs) and decreased Schwann cell density in vitro. In this study, we want to know whether cochlear implant-based electrical stimulation can induce the change of electrical activity in cultured SGNs.
Spiral ganglion neuron electrical stimulation in vitro model is established using the devices delivering cochlear implant-based electrical stimulation. After 48 h treatment by 50 A or 100 A electrical stimulation, the action potential (AP) and voltage depended calcium current ( ) of SGNs are recorded using whole-cell electrophysiological method.
The results show that the of SGNs is decreased significantly in 50 A and 100 A electrical stimulation groups. The reversal potential of is nearly +80 mV in control SGN, but the reversal potential decreases to +50 mV in 50 A and 100 A electrical stimulation groups. Interestingly, the AP amplitude, the AP latency, and the AP duration of SGNs have no statistically significant differences in all three groups.
Our study suggests cochlear implant-based electrical stimulation only significantly inhibit the of cultured SGNs but has no effect on the firing of AP, and the relation of inhibition and SGN damage induced by electrical stimulation and its mechanism needs to be further studied.
基于耳蜗植入的电刺激可能是导致耳蜗植入后残余听力损失的一个重要原因。在我们之前的研究中，我们发现平衡双相电刺激抑制了螺旋神经节神经元（SGN）的轴突生长，并减少了体外施万细胞的密度。在这项研究中，我们想知道基于耳蜗植入的电刺激是否会引起培养的 SGN 电活动的变化。
使用传递基于耳蜗植入的电刺激的设备建立体外 SGN 电刺激模型。在 50 A 或 100 A 电刺激处理 48 小时后，使用全细胞膜片钳电生理方法记录 SGN 的动作电位（AP）和电压依赖性钙电流（）。
结果表明，在 50 A 和 100 A 电刺激组中，SGN 的钙电流显著减少。SGN 中钙电流的反转电位在对照 SGN 中接近+80 mV，但在 50 A 和 100 A 电刺激组中，反转电位降低至+50 mV。有趣的是，在所有三组中，AP 幅度、AP 潜伏期和 AP 持续时间均无统计学差异。
我们的研究表明，基于耳蜗植入的电刺激仅显著抑制培养的 SGN 的钙电流，但对 AP 的发放没有影响，电刺激诱导的钙电流抑制与 SGN 损伤之间的关系及其机制需要进一步研究。
