2026-04-17T07:49:55Zhttps://recercat.cat/oai/request

oai:recercat.cat:10256/116192024-05-21T10:35:51Zcom_2072_452955com_2072_2054col_2072_452960

00925njm 22002777a 4500 dc Sedó Cabezón, Lara author Jedynak, Paulina author Boadas i Vaello, Pere author Llorens Baucells, Jordi author 2015 Ototoxicity is known to cause permanent loss of vestibule function through degeneration of sensory hair cells (HCs). However, functional recovery has been reported during washout after chronic ototoxicity, although the mechanisms underlying this reversible dysfunction are unknown. Here, we study this question in rats chronically exposed to the ototoxic compound 3,3'-iminodipropionitrile (IDPN). Pronounced alterations in vestibular function appeared before significant loss of HCs or stereociliary coalescence became evident by ultrastructural analyses. This early dysfunction was fully reversible if the exposure was terminated promptly. In cristae and utricles, the distinct junctions formed between type I HCs (HCI) and calyx endings were completely dismantled at these early stages of reversible dysfunction, and completely rebuilt during washout. Immunohistochemical observations revealed loss and recovery of the junction proteins CASPR1 and tenascin-C and RT-PCR indicated that their loss was not due to decreased gene expression. KCNQ4 was mislocalized during intoxication and recovered control-like localization after washout. At early stages of the intoxication, the calyces could be classified as showing intact or lost junctions, indicating that calyceal junction dismantlement is triggered on a calyx-by-calyx basis. Chronic toxicity also altered the presence of ribeye, PSD-95 and GluA2 puncta in the calyces. These synaptic alterations varied between the two types of calyx endings (formed by calyx-only or dimorphic afferents) and some persisted at the end of the washout period. The present data reveal new forms of plasticity of the calyx endings in adult mammals, including a robust capacity for rebuilding the calyceal junction. These findings contribute to a better understanding of the phenomena involved in progressive vestibular dysfunction and its potential recovery during and after ototoxic exposure This study was supported by the Ministry of Economy and Competitiveness (Spain)/ European Regional Development Fund (European Union) [BFU2012-31164]; and by the Agència de Gestiód’Ajuts Universitaris i de Recerca (Catalonia) [2014 SGR 943]. Deposited in PMC for immediate release http://hdl.handle.net/10256/11619 Toxicologia Toxicology Efectes secundaris dels medicaments Drugs -- Side effects Aparell vestibular Vestibular apparatus Transient alteration of the vestibular calyceal junction and synapse in response to chronic ototoxic insult in rats