Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, China.
Neurosci Lett. 2020 Jan 1;714:134536. doi: 10.1016/j.neulet.2019.134536. Epub 2019 Oct 4.
Spiral ganglion neurons (SGNs) are primary afferent auditory neurons activated by inner hair cells in mammalian cochlea. Here, for the convenience of SGN studies such as patch-clamp or single cell RNA-sequence studies, a knock-in mouse (Shh; Rosa26-Tdtomato) was generated for the purpose of obtaining fluorescence SGNs. Auditory brainstem response (ABR) and Tuj1 immunohistochemistry staining were performed to verify the hearing function and the morphological characteristics. The results showed that there was no significant difference between shh and wild type mice. In electrophysiological studies, we verified a series of electrophysiological characteristics including the amplitude of sodium and potassium currents and action potential characteristics of shh and wild type mice and no significant differences were found either. From the above, shh mice have the same cell function and morphology as their littermate control wild type mice and could be used as an ideal tool to study the function and characteristics of spiral ganglion neurons. Potassium channels of SGNs play an important role in resolving time accuracy. We obtained similar amplitude of I in neonatal and mature mice in the aging competition experiment, however, the density of I from mature mice were significantly different from those of neonatal mice, a phenomenon that may play a key role in the nervous system. Potassium channels have been shown to contribute to apoptosis induced by cisplatin administration in various cell lines. Here we used cisplatin administration to study the ototoxicity and found that the effects of a low dose of cisplatin (0.5 mM correspond to therapeutic doses) causes a decrease in currents and is reversible after a short administration time. Moreover, we propose the activated state of potassium channels has changed but the characteristic and number remain still after cisplatin administration. The excess potassium ions may accumulate in the cell body, which had affected the firing properties and induce cytotoxicity and apoptosis. We suggest that the electrophysiological properties of acutely isolated SGNs may support further research on the mechanics of auditory propagation and ion channel pharmacology.
螺旋神经节神经元（SGN）是哺乳动物耳蜗内毛细胞激活的初级传入听觉神经元。在这里，为了便于 SGN 的研究，例如膜片钳或单细胞 RNA 测序研究，生成了一种 Shh 敲入小鼠（Rosa26-Tdtomato），用于获得荧光 SGN。进行了听觉脑干反应（ABR）和 Tuj1 免疫组织化学染色，以验证听力功能和形态特征。结果表明，shh 与野生型小鼠之间没有显着差异。在电生理研究中，我们验证了一系列电生理特性，包括钠和钾电流的幅度以及 shh 和野生型小鼠的动作电位特性，也没有发现显着差异。综上所述，shh 小鼠具有与其同窝野生型对照小鼠相同的细胞功能和形态，可作为研究螺旋神经节神经元功能和特性的理想工具。SGN 的钾通道在解决时间精度方面起着重要作用。在衰老竞争实验中，我们在新生和成熟小鼠中获得了相似幅度的 I，然而，成熟小鼠的 I 密度与新生小鼠的显著不同，这一现象可能在神经系统中起关键作用。钾通道已被证明有助于各种细胞系中顺铂给药诱导的细胞凋亡。在这里，我们使用顺铂给药来研究耳毒性，发现低剂量顺铂（0.5mM 对应于治疗剂量）的作用会导致电流减少，并且在短时间给药后是可逆的。此外，我们提出钾通道的激活状态在顺铂给药后已经改变，但特征和数量仍然保持不变。过多的钾离子可能在细胞体中积累，这已经影响了放电特性并诱导细胞毒性和细胞凋亡。我们建议急性分离的 SGN 的电生理特性可能支持进一步研究听觉传播的力学和离子通道药理学。
