Department of Otorhinolaryngology‑Head and Neck Surgery, National Medical Center, Seoul 04564, Republic of Korea.
Department of Otorhinolaryngology‑Head and Neck Surgery, Chung‑Ang University College of Medicine, Seoul 06974, Republic of Korea.
Int J Mol Med. 2021 Jul;48(1). doi: 10.3892/ijmm.2021.4969. Epub 2021 May 26.
Changes in the dorsal cochlear nucleus (DCN) following exposure to noise play an important role in the development of tinnitus. As the development of several diseases is known to be associated with microRNAs (miRNAs/miRs), the aim of the present study was to identify the miRNAs that may be implicated in pathogenic changes in the DCN, resulting in tinnitus. A previously developed tinnitus animal model was used for this study. The study consisted of four stages, including identification of candidate miRNAs involved in tinnitus development using miRNA microarray analysis, validation of miRNA expression using reverse transcription‑quantitative PCR (RT‑qPCR), evaluation of the effects of candidate miRNA overexpression on tinnitus development through injection of a candidate miRNA mimic or mimic negative control, and target prediction of candidate miRNAs using mRNA microarray analysis and western blotting. The miRNA microarray and RT‑qPCR analyses revealed that miR‑375‑3p expression was significantly reduced in the tinnitus group compared with that in the non‑tinnitus group. Additionally, miR‑375‑3p overexpression via injection of miR‑375‑3p mimic reduced the proportion of animals with persistent tinnitus. Based on mRNA microarray and western blot analyses, connective tissue growth factor () was identified as a potential target for miR‑375‑3p. Thus, it was inferred that CTGF downregulation by miR‑375‑3p may weaken with the decrease in miRNA expression, and the increased pro‑apoptotic activity of CTGF may result in more severe neuronal damage, contributing to tinnitus development. These findings are expected to contribute significantly to the development of a novel therapeutic approach to tinnitus, thereby bringing about a significant breakthrough in the treatment of this potentially debilitating condition.
耳蜗背核（DCN）在噪声暴露后的变化在耳鸣的发展中起着重要作用。由于已知几种疾病的发展与 microRNAs（miRNAs/miRs）有关，本研究旨在确定可能与 DCN 致病变化有关的 miRNAs，从而导致耳鸣。本研究使用了先前开发的耳鸣动物模型。该研究包括四个阶段，包括使用 miRNA 微阵列分析鉴定参与耳鸣发展的候选 miRNA，使用逆转录-定量 PCR（RT-qPCR）验证 miRNA 表达，通过注射候选 miRNA 模拟物或模拟物阴性对照评估候选 miRNA 过表达对耳鸣发展的影响，以及使用 mRNA 微阵列分析和 Western blot 预测候选 miRNA 的靶标。miRNA 微阵列和 RT-qPCR 分析显示，与非耳鸣组相比，耳鸣组 miR-375-3p 的表达显著降低。此外，通过注射 miR-375-3p 模拟物过表达 miR-375-3p 可降低持续耳鸣动物的比例。基于 mRNA 微阵列和 Western blot 分析，结缔组织生长因子（CTGF）被鉴定为 miR-375-3p 的潜在靶标。因此，可以推断出 miR-375-3p 下调 CTGF 可能会随着 miRNA 表达的降低而减弱，而 CTGF 的促凋亡活性增加可能导致更严重的神经元损伤，导致耳鸣的发展。这些发现有望为耳鸣的新型治疗方法的发展做出重大贡献，从而在这种潜在致残疾病的治疗方面取得重大突破。
