Autophagy-related protein 12 associates with anti-apoptotic B cell lymphoma-2 to promote apoptosis in gentamicin-induced inner ear hair cell loss

摘要

The aim of the present study was to investigate the underlying mechanisms of autophagy in a gentamicin (GM)-induced ototoxic model, and to establish whether the blocking of autophagy significantly increases the survival of inner ear hair cells. Cochleae were carefully dissected from four day-old C57BL/6J mice and randomly divided into three groups prior to explant culture: Control (culture medium), GM-treated (culture medium + GM) and GM + 3-methylad-enine (3-MA; culture medium + GM + 3-MA). Transmission electron microscopy, immunofluorescence and western blotting were performed to observe the expression of the autophagy protein microtubule-associated protein 1A/B-light chain 3 in explant cultures treated with GM and the autophagy inhibitor 3-MA. Administration of GM in in vitro mouse cochlear culture induced apoptosis and the formation of autophagic vesicles and autophagosomes in hair cells. Notably, combined treatment with GM and 3-MA to block autophagy significantly increased the survival of inner ear hair cells. Furthermore, it was indicated that the simultaneous expression and interaction of Atg12 with Bcl-2 following GM treatment co-integrated autophagy with apoptosis in the cochlea. The results of the present study demonstrated that autophagy was involved in GM-induced ototoxicity. Additionally, Atg12 may serve a protective role by binding to Bcl-2. Therefore, Atg12 may be a potential therapeutic target for the treatment of GM-induced cochlear hair loss.