Apelin-13 Protects Inner Ear Hair Cells From Oxidative Stress-Induced Apoptosis In Vitro and In Vivo

Background and Aim: Several studies have shown that exposure toloud sounds leads to the formation of oxidative stress and free radicalsin particular hydrogen peroxide (H2O2) in tissue. Apelin-13 is anadipocytokine that was first isolated from the bovine stomach extract.Recent studies have shown that apelin-13 has protective effects onthe brain s ischemia-induced cell death and injury. Apelin-13 also hasprotective effects on the hippocampal cells and cortical neurons againstoxidative stress. However, the protective effects of apelin-13 on the innerear hair cells are not known. Therefore, in this study, we evaluated theprotective effects of apelin-13 on the cochlear hair cell damage inducedby oxidative stress in a culture medium and in vivo.Methods: Stem cells were differentiated into hair cell-like cell by B27,FGF, EGF, and IGF-1. Expression of neuron-specific markers including βtubulin III, Nestin, MAP2, Neurofilament, and GFAP was tested by flowcytometry assay. As well, inner ear hair cell marker such as Myosin7, Sox2, TrkB and AchR α expression was assayed with immunocytochemistry(ICC). Protective effect of apelin-13 was assayed in H2O2 - treated haircells in vitro by acridine-orange staining. For in vivo assay, rats wereassigned into control, noise exposure groups without any treatment orreceiving apelin-13. Following chronic exposure to 110 dB white noise,apelin-13 was injected i.p, then histological, molecular and tunnel assaywas done.Results: Our findings show that apelin -13 protect hair cell-like celldamage against oxidative stress in vitro condition. As well, apelin-13reduced cochlear hair cell death in a rat model of noise-induced hearingloss (NIHL) by inhibition of apoptosis.Conclusion: Our study suggested that apelin-13 could be a promisingtarget to treat noise-induced hearing loss (NIHL) through reducingapoptosis. Although more research is needed to investigate the potentialtherapeutic effects of apelin-13 in NIHL patients.

کلیدواژه ها:

Apelin-13 ، Stress Oxidative ، Hair Cell ، Apoptosis