The SCN11A gene, encoded Nav1.9 TTX resistant sodium channels, is a main effector in peripheral inflammation related pain in nociceptive neurons. The role of SCN11A gene in the auditory system has not been well characterized. We therefore examined the expression of SCN11A in the murine cochlea, the morphological and physiological features of Nav1.9 knockout (KO) ICR mice. Nav1.9 expression was found in the primary afferent endings beneath the inner hair cells (IHCs). The relative quantitative expression of Nav1.9 mRNA in modiolus of wild-type (WT) mice remains unchanged from P0 to P60. The number of presynaptic CtBP2 puncta in Nav1.9 KO mice was significantly lower than WT. In addition, the number of SGNs in Nav1.9 KO mice was also less than WT in the basal turn, but not in the apical and middle turns. There was no lesion in the somas and stereocilia of hair cells in Nav1.9 KO mice. Furthermore, Nav1.9 KO mice showed higher and progressive elevated ABR threshold at 16 kHz, and a significant increase in CAP thresholds. These data suggest a role of Nav1.9 in regulating the function of ribbon synapses and the auditory nerves. The impairment induced by Nav1.9 gene deletion mimics the characters of cochlear synaptopathy.

中文翻译：

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SCN11A基因缺失通过损害带状突触和听觉神经导致感音神经性听力损失

SCN11A 基因编码 Nav1.9 TTX 抗性钠通道，是伤害性神经元外周炎症相关疼痛的主要效应物。SCN11A 基因在听觉系统中的作用尚未得到很好的表征。因此，我们检查了 SCN11A 在鼠耳蜗中的表达、Nav1.9 敲除 (KO) ICR 小鼠的形态学和生理学特征。在内毛细胞 (IHC) 下方的初级传入神经末梢中发现了 Nav1.9 表达。Nav1.9 mRNA 在野生型 (WT) 小鼠耳轮中的相对定量表达从 P0 到 P60 保持不变。Nav1.9 KO小鼠突触前CtBP2点的数量显着低于WT。此外，Nav1.9 KO小鼠中SGNs的数量在基底转中也少于WT，但在顶端和中转中没有。Nav1.9 KO小鼠毛细胞胞体和毛细胞静纤毛未见病变。此外，Nav1.9 KO 小鼠在 16 kHz 时表现出更高且逐渐升高的 ABR 阈值，并且 CAP 阈值显着增加。这些数据表明 Nav1.9 在调节带状突触和听觉神经的功能方面发挥了作用。Nav1.9 基因缺失引起的损伤模仿耳蜗突触病的特征。