Research Progress in Species Differences and Underlying Physiological Mechanism of Noise-induced Hearing Loss

Noise widely exists in animals and human everyday life, it has negative influence on animals from invertebrates to mammals, and even human beings. High level noise can cause damage to auditory structure and function, decrease auditory neural sensitivity and behavioral acuity, and even lead to noise-induced hearing loss (NIHL). In this review, we summarized influence impacts and classification of NIHL, and possible mechanisms underlying the NIHL. Previous research on NIHL showed that the NIHL was related to postsynaptic terminals swelling, reversible excitotoxicity induced by glutamate and reactive oxygen species (ROS) evoked oxidative stress, cell apoptosis, synaptic ribbons damage and increasing express level of mRNA of guanine nucleotide binding protein alpha stimulating (GNAS) and their upstream lncRNAs Sept7. We further compared the differences in hearing loss among different species, and found that all species exhibited various degree of hearing loss after noise exposure excepting the echolocation bats. The fishes and birds can quickly recover from the hearing damage because their hair cells have the ability to regenerate. Comparing with the rodent which is more susceptive to noise influence, the echolocation cetacean have a small temporary threshold shift (US) after high intensity noise exposure, and the specialized inner ear structure is thought to be the possible reason. It is interesting that the echolocation bat do not exhibit US even exposed to high intensity noise, which is thought to be an adaption to their living environment, and forward studies on the underlying neurophysiological mechanisms will help us fully understand and solve the NIHL. These conclusions indicated that comparative physiological study on different species can help us deeply reveal the mechanism underlying NIHL, and provide a reference for hearing protection and repairing of noise induced hearing loss.