Protective Effect And Mechanism Of Dihydromyricetin Against Aminoglycosides-Induced Ototoxicity

Objective: Aminoglycoside antibiotics,because of their low price and antimicrobial effectiveness,are still the most widely used antibiotics worldwide.But during its clinical application,it has obvious ototoxic side effects,severely affecting the quality of life of patients as well as causing a heavy burden for socioeconomic development.Numerous studies have shown that aminoglycoside antibiotic induced inner ear injury is associated with the oxidative stress response.Aminoglycoside antibiotics,when administered into the inner ear,stimulate the production of large amounts of reactive oxygen species(ROS)within hair cells.Excessive accumulation of ROS damages DNA,lipids,and proteins in cochlear hair cells and induces initiation of apoptotic pathways that in turn cause cell death.Dihydromyricetin(DHM)is a natural flavonol with a wide range of health benefits,including anti-inflammatory,antitumor,and antioxidant effects.However,its role and mechanism of action in auditory hair cells are unknown.This study investigated the antiototoxic potential effect of dihydromyricetin as well as the antioxidant mechanism of action using the house ear Institute organ of Corti(HEI-OC)1 auditory cells and cultured cochlear tissues prepared from Kunming mice.Methods:(1)Ototoxic model induced by aminoglycoside antibiotic was established using gentamicin.(2)The pharmacological effects of dihydromyricetin on gentamicin induced ototoxicity were determined by using immunofluorescence experiments,cell viability assay experiments,and so on.(3)The effect of dihydromyricetin on gentamicin induced apoptosis was determined by terminal deoxynucleotidyl transferase mediated d UTP nick end labeling(TUNEL)assay,cell flow assay,and Western blot assay.(4)The effect of dihydromyricetin on cellular oxidative stress injury caused by gentamicin was examined using a cell flow assay.(5)Western blot,quantitative RT-PCR analysis,cell viability assay,immunofluorescence assay,TUNEL staining assay were utilized to examine the mechanism of PGC-1α and SIRT3 in exerting ototoxic protective function by dihydromyricetin.Results:(1)Gentamicin could cause auditory cell viability decrease,whereas the viability of auditory cells increased with the pretreatment of dihydromyricetin.(2)Dihydromyricetin could inhibit the apoptotic damage caused by gentamicin.(3)Dihydromyricetin could inhibit cellular oxidative stress injury caused by gentamicin.(4)Dihydromyricetin inhibited gentamicin caused apoptosis and oxidative stress responses by activating the PGC-1α / SIRT3 signaling pathway,which in turn exerted ototoxic protective effects.Conclusion: Our study is the first to identify dihydromyricetin as potentially ototoxic protective and provides a basis for the prevention and treatment of hearing loss caused by aminoglycoside antibiotics induced oxidative damage to auditory hair cells.