Transcriptomic analysis reveals prolonged neurodegeneration in the hippocampus of adult C57BL/6N mouse deafened by noise

Sang-Youp Lee; Ho Sun Lee; Min-Hyun Park

doi:10.3389/fnins.2024.1340854

Transcriptomic analysis reveals prolonged neurodegeneration in the hippocampus of adult C57BL/6N mouse deafened by noise

Front Neurosci. 2024 Feb 12:18:1340854. doi: 10.3389/fnins.2024.1340854. eCollection 2024.

Authors

Sang-Youp Lee¹, Ho Sun Lee^{1

2}, Min-Hyun Park^{1

2}

Affiliations

¹ Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul, Republic of Korea.
² Department of Otorhinolaryngology, Boramae Medical Center, Seoul Metropolitan Government-Seoul National University, Seoul, Republic of Korea.

Abstract

Introduction: Several studies have reported a significant correlation between noise-induced hearing loss and cognitive decline. However, comprehensive analyses of this relationship are rare. This study aimed to assess the influence of hearing impairment on cognitive functions by analyzing organ samples in the afferent auditory pathway of deafened mice using mRNA sequencing.

Methods: We prepared 10 female 12-week-old C57BL/6N mice as the experimental and control groups in equal numbers. Mice in the experimental group were deafened with 120 dB sound pressure level (SPL) wideband noise for 2 h. Cochlea, auditory cortex, and hippocampus were obtained from all mice. After constructing cDNA libraries for the extracted RNA from the samples, we performed next-generation sequencing. Subsequently, we analyzed the results using gene ontologies (GOs) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway databases for differentially expressed genes (DEGs) of each organ.

Results: Our results revealed 102, 89, and 176 DEGs for cochlea, auditory cortex, and hippocampus, respectively. We identified 294, 203, and 211 GOs; 10, 7, and 17 KEGG pathways in the cochlea, auditory cortex, and hippocampus, respectively. In the long term (12 weeks) from noise-induced hearing loss, GOs and KEGG pathways related to apoptosis or inflammation persisted more actively in the order of hippocampus, auditory cortex, and cochlea.

Discussion: This implies that the neurodegenerative effects of noise exposure persist more longer time in the central regions.

Keywords: auditory cortex; cochlea; hippocampus; neurodegeneration; noise-induced hearing loss; transcriptomics.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was supported by the Korea National Research Fund (NRF-2020R1A2C1006254; PI: M-HP). The funding body played no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.