Tinnitus is a common auditory disease worldwide; it is estimated that more than 10% of all individuals experience this hearing disorder during their lifetime. Tinnitus is sometimes accompanied by hearing loss. However, hearing loss is not acquired in some other tinnitus generations. In this study, we injected adult rats with salicylate sodium (SS) (200 mg/kg/day for 10 days) and found no significant hearing threshold changes at 2, 4, 8, 12, 14, 16, 20, or 24 kHz (all ). Tinnitus was confirmed in the treated rats via Behaviour Testing of Acoustic Startle Response (ASR) and Gap Prepulse Inhibition Test of Acoustic Startle Reflex (GPIAS). A immunostaining study showed that there is significant loss of anti-CtBP2 puncta (a marker of cochlear inner hair cell (HC) ribbon synapses) in treated animals in apical, middle, and basal turns (all ). The ABR wave I amplitudes were significantly reduced at 4, 8, 12, 14, 16, and 20 kHz (all ). No significant losses of outer HCs, inner HCs, or HC cilia were observed (all ). Thus, our study suggests that loss of cochlear inner HC ribbon synapse after SS exposure is a contributor to the development of tinnitus without changing hearing threshold.

中文翻译：

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耳蜗带状突触的丧失是慢性水杨酸钠治疗诱发的耳鸣的关键因素，而耳鸣阈值没有变化。

耳鸣是全世界常见的听觉疾病；据估计，超过10％的个体在一生中都会经历这种听力障碍。耳鸣有时伴有听力下降。但是，在其他一些耳鸣世代中并没有获得听力损失。在这项研究中，我们给成年大鼠注射了水杨酸钠（SS）（200 mg / kg /天，持续10天），并且在2、4、8、12、14、16、20或24 kHz时未发现明显的听力阈值变化（所有）。通过声学惊吓反应（ASR）的行为测试和声学惊吓反射（GPIAS）的间隙预脉冲抑制测试，在治疗的大鼠中确认了耳鸣。一项免疫染色研究表明，在受治疗的动物的顶端，中部和基础部位转弯处，抗CtBP2点（耳蜗内毛细胞（HC）带状突触的标志物）明显丢失（所有）。在4、8、12、14、16和20 kHz时ABR波I的幅度显着降低了（所有）。没有观察到外部HC，内部HC或HC纤毛的明显损失（所有）。因此，我们的研究表明，SS暴露后耳蜗内HC丝带突触的丧失是耳鸣发展的一个原因，而不会改变听力阈值。