Exosomes derived from TNF-α preconditioned bone marrow mesenchymal stem cells alleviate cisplatin-induced ototoxicity in mice

The polarization of microglia promotes the development of cisplatin-induced ototoxicity, and exosomes (Exo) derived from TNF-α preconditioned mesenchymal stem cells (MSCs) may induce the polarization of macrophage. Mice were intraperitoneally injected with cisplatin to establish the ototoxicity model. Bone marrow MSCs (BMSCs) were preconditioned with TNF-α for 48 h, and the relevant TNF-Exo or Exo was enriched, which were further trans-tympanically administered in the left ear of ototoxic mice. Auditory sensitivity was revealed with auditory brainstem response (ABR) at 8, 16, 24, and 32 kHz. The number of hair cells was detected with Myosin 7a staining. Damaged auditory sensitivity and up-regulated hair cell loss were revealed in cisplatin-exposed mice, which could be reversed by Exo or TNF-Exo treatment. Mechanically, up-regulated Iba1, Cd86, iNOS, Cd206, and Arg1 were detected in cisplatin-exposed cochlea. TNF-Exo or Exo administration further decreased Iba1, Cd86, and iNOS expression, and increased cd206 and Arg1 expression. TNF-Exo or Exo administration inhibited the productin of pro-inflammatory cytokines (IL-1β and IL-6), while enhanced the anti-inflammatory cytokine IL-10 production in the cisplatin-exposed cochlea. Importantly, TNF-Exo administration showed more profound benefits compared with Exo. TNF-α preconditioning might be a new therapeutic option to enhance the capability of BMSCs-derived exosomes against cisplatin-induced ototoxicity.