Damage and functional recovery of the Atlantic cod (Gadus morhua) inner ear hair cells following local injection of gentamicin.
This study addresses the ultrastructural and functional damage and subsequent recovery of the inner ear in the Atlantic cod following intrasaccular gentamicin injection. Inner ear damage was assessed using SEM and measurements of AEP following 250-Hz pure-tone stimuli. Data from gentamicin-treated fish were compared with control (no injection) and sham (injection of saline) fish. Control fish had normal response thresholds associated with well-developed hair cell bundles in their macula sacculi. Sham fish had higher response thresholds compared with control fish during the first week post-intervention, but response thresholds were subsequently normal. Treated fish displayed significant inner ear damage associated with an increased average AEP threshold on the third day following treatment. Thereafter, inner ear tissue displayed signs of progressive regeneration until it was comparable to controls from the 14th day. Response thresholds were similar to those of control fish from the 17th day following treatment. These observations suggest that the macula sacculi of Atlantic cod can regenerate towards a near-complete functional and ultrastructural recovery within 17-21 days following ototoxic gentamicin treatment.
Faucher
Karine
K
ENT Department, Institute of Clinical Medicine, University of Tromsø, Norway. kfaucher@hotmail.fr
Aas-Hansen
Øyvind
Ø
Damsgård
Borge
B
Laukli
Einar
E
Stenklev
Niels Christian
NC
D008267:Acoustic Maculae / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D000161:Acoustic Stimulation; D000704:Analysis of Variance; D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D001307:Auditory Perception / Q000502:physiology; D001309:Auditory Threshold; D005072:Evoked Potentials, Auditory; D048389:Gadus morhua; D005839:Gentamicins / Q000633:toxicity*; D006198:Hair Cells, Auditory / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D007759:Labyrinth Diseases / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D008855:Microscopy, Electron, Scanning; D020127:Recovery of Function; D012038:Regeneration; D013997:Time Factors
D000900:Anti-Bacterial Agents; D005839:Gentamicins