Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
Int J Mol Sci. 2022 May 6;23(9):5179. doi: 10.3390/ijms23095179.
There is growing evidence for a relationship between gut dysbiosis and hearing loss. Inflammatory bowel disease, diet-induced obesity (DIO), and type 2 diabetes have all been linked to hearing loss. Here, we investigated the effect of a chronic high-fat diet (HFD) on the development of inner ear inflammation using a rodent model. Three-week-old CD-1 (Swiss) mice were fed an HFD or a control diet for ten weeks. After ten weeks, mouse cochleae were harvested, and markers of cochlear inflammation were assessed at the protein level using immunohistochemistry and at the gene expression level using quantitative real-time RT-PCR. We identified increased immunoexpression of pro-inflammatory biomarkers in animals on an HFD, including intracellular adhesion molecule 1 (ICAM1), interleukin 6 receptor α (IL6Rα), and toll-like-receptor 2 (TLR2). In addition, increased numbers of ionized calcium-binding adapter molecule 1 (Iba1) positive macrophages were found in the cochlear lateral wall in mice on an HFD. In contrast, gene expression levels of inflammatory markers were not affected by an HFD The recruitment of macrophages to the cochlea and increased immunoexpression of inflammatory markers in mice fed an HFD provide direct evidence for the association between HFD and cochlear inflammation.
越来越多的证据表明肠道菌群失调与听力损失之间存在关系。炎症性肠病、饮食诱导的肥胖（DIO）和 2 型糖尿病都与听力损失有关。在这里，我们使用啮齿动物模型研究了慢性高脂肪饮食（HFD）对内耳炎症发展的影响。将 3 周龄的 CD-1（瑞士）小鼠用 HFD 或对照饮食喂养 10 周。10 周后，收获小鼠耳蜗，并使用免疫组织化学法在蛋白质水平上评估耳蜗炎症标志物，使用定量实时 RT-PCR 在基因表达水平上评估。我们发现 HFD 组动物中促炎生物标志物的免疫表达增加，包括细胞间粘附分子 1（ICAM1）、白细胞介素 6 受体 α（IL6Rα）和 Toll 样受体 2（TLR2）。此外，在 HFD 组小鼠的耳蜗外侧壁中发现了更多的离子钙结合接头分子 1（Iba1）阳性巨噬细胞。相比之下，HFD 并未影响炎症标志物的基因表达水平。巨噬细胞向耳蜗的募集和 HFD 喂养小鼠中炎症标志物的免疫表达增加为 HFD 与耳蜗炎症之间的关联提供了直接证据。
