Noise-Induced Hearing Loss (NIHL) as a Target of Oxidative Stress-Mediated Damage: Cochlear and Cortical Responses after an Increase in Antioxidant Defense

Abstract

This study addresses the relationship between cochlear oxidative damage and auditory cortical injury in a rat model of repeated noise exposure. To test the effect of increased antioxidant defenses, a water-soluble coenzyme Q 10 analog (Q ter ) was used. We analyzed auditory function, cochlear oxidative stress, morphological alterations in auditory cortices and cochlear structures, and levels of coenzymes Q 9 and Q 10 (CoQ 9 and CoQ 10 , respectively) as indicators of endogenous antioxidant capability. We report three main results. First, hearing loss and damage in hair cells and spiral ganglion was determined by noise-induced oxidative stress. Second, the acoustic trauma altered dendritic morphology and decreased spine number of II-III and V-VI layer pyramidal neurons of auditory cortices. Third, the systemic administration of the water-soluble CoQ 10 analog reduced oxidative-induced cochlear damage, hearing loss, and cortical dendritic injury. Furthermore, cochlear levels of CoQ 9 and CoQ 10 content increased. These findings indicate that antioxidant treatment restores auditory cortical neuronal morphology and hearing function by reducing the noise-induced redox imbalance in the cochlea and the deafferentation effects upstream the acoustic pathway.

Curcuma Longa (Curcumin) Decreases In Vivo Cisplatin-Induced Ototoxicity Through Heme Oxygenase-1 Induction

“…Rh-Ph staining was performed at Days 3 and 5 in 45 animals. As described previously (26), surface preparations of the organ of Corti were incubated with a solution containing 0.5% Triton X-100 and Rh-Ph (1:100 dilution; Molecular Probes, Invitrogen, Carlsbad, CA, USA) in 0.1 M PBS for 1 hour at room temperature protected from light. Positive cells were counted in segments of approximately 250 Km in length each along the basilar membrane.…”

Ferulic acid attenuates brain microvascular endothelial cells damage caused by oxygen-glucose deprivation via punctate-mitochondria-dependent mitophagy

“…In addition, FA is an effective component of Chinese medicinal herbs, such as Angelica sinensis, Cimicifuga heracleifolia Komar and Lycium barbarum (Ou and Kwok, 2004) and has a beneficial effect on scavenging free radicals. Nowadays, it has been approved beneficial for a variety of serious chronic diseases, such as intestinal ischemia (Huang, 2015), cancer (Serafim et al, 2011), cardiovascular disease (Ardiansyah et al, 2008), skin diseases (Lin et al, 2005), diabetes (Jung et al, 2007), cochlea oxidative damage caused by repeated noise exposure (Fetoni et al, 2013), and oxidative stress of human dermal fibroblasts (Calabrese et al, 2008). In addition, the free radical scavenging activity of FA can relieve a variety of neurodegenerative disease, especially Alzheimer's disease (Sgarbossa et al, 2015;Sultana, 2012).…”

Resveratrol Promotes Recovery of Hearing following Intense Noise Exposure by Enhancing Cochlear SIRT1 Activity

“…Second, in addition to the cochlea, noise exposure also leads to morphological and electrophysiological modifications in the central auditory system [Eggermont, 2017]. For example, both terminal and total spine densities in dendrites of layers II-III and V-VI of the auditory cortex are significantly decreased following noise exposure [Fetoni et al, 2013]. Further research is needed to assess the protective role of resveratrol on the central auditory system.…”

“…Oxidative stress is essentially an imbalance between production of reactive oxygen species (ROS) and antioxidant defenses. Overproduction of ROS is believed to be a major cause of NIHL, and antioxidants have been shown to attenuate noise-induced hair cell death and NIHL [Fetoni et al, 2013;Henderson et al, 2006].…”