Prevention of noise-induced hearing loss by calpain inhibitor MDL-28170 is associated with upregulation of PI3K/Akt survival signaling pathway

Hesperidin activates Nrf2 to protect cochlear hair cells from cisplatin-induced damage

Cisplatin is widely employed in clinical oncology as an anticancer chemotherapy drug in clinical practice and is known for its severe ototoxic side effects. Prior research indicates that the accumulation of reactive oxygen species (ROS) plays a pivotal role in cisplatin's inner ear toxicity. Hesperidin is a flavanone glycoside extracted from citrus fruits that has anti-inflammatory and antioxidant effects. Nonetheless, the specific pharmacological actions of hesperidin in alleviating cisplatin-induced ototoxicity remain elusive. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a critical mediator of the cellular oxidative stress response, is influenced by hesperidin. Activation of Nrf2 was shown to have a protective effect against cisplatin-induced ototoxicity. The potential of hesperidin to stimulate Nrf2 in attenuating cisplatin's adverse effects on the inner ear warrants further investigation. This study employs both in vivo and in vitro models of cisplatin ototoxicity to explore this possibility. Our results reveal that hesperidin mitigates cisplatin-induced ototoxicity by activating the Nrf2/NQO1 pathway in sensory hair cells, thereby reducing ROS accumulation, preventing hair cell apoptosis, and alleviating hearing loss.

Effects of Astragaloside IV on Hearing, Inflammatory Factors, and Intestinal Flora in Mice Exposed to Noise

Long-term exposure to noise can cause irreversible hearing loss. Considering that there is no effective drug treatment, it is important to seek preventive treatment for noise-induced hearing loss (NIHL). Although astragaloside IV (AS-IV) protects against NIHL by reducing serum inflammatory factors, there is scarce information on the regulation of inflammatory factors by AS-IV to prevent NIHL. We investigated the hearing thresholds and relationship between the serum levels of inflammatory cytokines and intestinal microbiota of c57bl/6j mice exposed to noise (103 dB SPL 4 h·d-1) for 7 days, treated with or without AS-IV. Our results revealed a lower hearing threshold and lower serum levels of TNF-α, TNF-γ, IL-6, IL-1β, and IFN-γ in the mice treated with AS-IV. Additionally, AS-IV increased the abundance levels of the phylum Firmicutes, class Bacillus, order Lactobacillus, and family Lactobacillus (p < 0.05), and decreased those of the phylum Bacteroidetes and order Bacteroidales (p < 0.05). Lactobacillus and Bacilli negatively correlated with TNF-α, TNF-γ, and IL-1β; Erysipelotrichaceae negatively correlated with INF-γ; and Clostridiales positively correlated with IL-1β. In conclusion, AS-IV reduces the elevation of hearing thresholds in mice, preventing hearing loss in mice exposed to noise, and under the intervention of AS-IV, changes in the levels of inflammatory factors correlate with intestinal flora. We suggest that AS-IV improves intestinal flora and reduces inflammation levels in c57bl/6j mice exposed to noise.

Study on Screening Core Biomarkers of Noise and Drug-Induced Hearing Loss Based on Transcriptomics

Background  Noise and drug-induced hearing loss (HL) is becoming more and more serious, but the integration and analysis based on transcriptomics and proteomics are lacking. On the one hand, this study aims to integrate existing public transcriptomic data on noise and gentamicin-induced HL. On the other hand, the study aims to establish the gentamicin and noise-induced HL model of guinea pigs, then to perform the transcriptomic and proteomic analyses. Through comprehensive analysis of the above data, we aim to screen, predict, and preliminarily verify biomarkers closely related to HL. Material and Methods  We screened the Gene Expression Omnibus database to obtain transcriptome data expression profiles of HL caused by noise and gentamicin, then constructed the guinea pig HL model and perform the transcriptomic and proteomic analyses. Differential expression and enrichment analysis were performed on public and self-sequenced data, and common differentially expressed genes (DEGs) and signaling pathways were obtained. Finally, we used proteomic data to screen for common differential proteins and validate common differential expression genes for HL. Results  By integrating the public data set with self-constructed model data set, we eventually obtained two core biomarkers of HL, which were RSAD2 and matrix metalloproteinase-3 (MMP3). Their main function is to regulate the development of sense organ in the inner ear and they are mainly involved in mitogen-activated protein kinase and phosphoinositol-3 kinase/protein kinase B signaling pathways. Finally, by integrating the proteomic data of the self-constructed model, we also found differential expression of MMP3 protein. This also preliminarily and partially verified the above-mentioned core biomarkers. Conclusion and Significance  In this study, public database and transcriptomic data of self-constructed model were integrated, and we screened out two core genes and various signal pathways of HL through differential analysis, enrichment analysis, and other analysis methods. Then, we preliminarily validated the MMP3 by proteomic analysis of self-constructed model. This study pointed out the direction for further laboratory verification of key biomarkers of HL, which is of great significance for revealing the core pathogenic mechanism of HL.