In vitro Modeling of Noise-Induced Hearing Loss using in vivo Data of Gene Expression Changes or Direct Noise Stimuli

Abstract

Noise-induced hearing loss (NIHL) significantly contributes to sensorineural hearing loss in modern society, with projections indicating a growing prevalence. This study aimed to investigate the underlying mechanisms of NIHL and develop relevant in vitro models for better understanding and potential therapeutic interventions. Initially, we established a NIHL animal model and performed RNA sequencing to analyze gene expression post-noise exposure. The results showed significant changes in genes associated with inflammation and reactive oxygen species (ROS), leading to apoptosis and necroptosis, alongside alterations in mitochondrial function. Based on these findings, we aimed to develop an in vitro disease model. We identified several key genes, including tumor necrosis factor ligand superfamily member 10 (Tnfsf10), and sought to develop an in vitro model that could induce similar changes. Building on these findings, we developed a thapsigargin (TG)-induced NIHL mimetic in vitro model and evaluated the efficacy of 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH), a compound known to enhance mitochondrial biogenesis and energy metabolism, both in vitro and in vivo. Although the TG-induced model was informative, it also induced ER stress, complicating its use as a pure NIHL model. Therefore, we directly applied noise stimulation to House Ear Institute-Organ of Corti 1 (HEI-OC1) cells to better mimic actual NIHL conditions. This noise-stimulated model exhibited changes similar to those observed in the in vivo NIHL model, including increased expression of inflammatory response genes and mitochondrial ROS production. Our results suggest that the noise-stimulated in vitro model is more representative of NIHL conditions. This model holds promise for advancing the study of NIHL mechanisms and could be particularly valuable as ethical considerations increasingly limit animal experiments. Future applications may include using this model to study inner ear organoids, further enhancing our understanding and treatment of NIHL._x000D_