| Abstrakt: |
Ototoxicity is defined as damage to the inner ear, targeting cochlear and vestibular structures and sensory function, due to exposure to certain pharmaceuticals or chemicals. Drug classes most associated with ototoxicity include antibiotics, such as aminoglycosides and platinum-based chemothera-peutic agents (cisplatin). Although ototoxicity mechanisms of action are not fully elucidated, much progress has been made in identifying otoprotective solutions and/or drug replacement with reduced or no ototoxicity. There are ongoing efforts to get alternative tests and techniques to the in vivo tests, to predict early in the development the ototoxicity risk, in a rapid manner and reduce the number of animals used for in vivo tests. Cochlear explants in neonatal rodents are an organotypic culture of the immature cochlea, facilitating the presentation of organized cellular structures within the inner ear, which are otherwise hard-to-access.The objective of this study was to develop the most accurate ototoxic ex vivo model, using rat and mice cochlear explants. The technical challenges are presented and discussed. We worked on the different components of the explant to provide the most relevant and reliable method to analyze drug ototoxic effects on the rodent cochlear explants: (1) the parameters characterizing the explant model: age of the pups, composition of culture medium, dissection method, ototoxic reference drug dose, duration of drug exposure and culture period. (2) the markers to visualize the various structures of the cochlea, such as hair cells, supporting cells, fibers, and neurons. (3) the method of image acquisition using a laser scanning confocal microscope and the histological analysis methods based on a qualitative and quantitative assessment of hair cells (scoring of hair cell organization and counting of hair cell numbers). The development of reliable and consistent rodent explant cultures provides significant advantages for investigating drug mechanisms of ototoxicity and developing novel therapies. Preclinical testing is a critical phase in new drug development, making it essential to continually refine and expand tools, including in vivo and in vitro models, to advance the progress of new treatments. Ultimately, these efforts contribute to reducing the burden of drug-induced hearing loss in clinical practice. [ABSTRACT FROM AUTHOR] |
