title: Gentamicin attenuates gentamicin-induced ototoxicity - self-protection.
abstract: Aminoglycoside antibiotics cause considerable toxicity to the inner ear. A progressive hearing loss at high frequencies resulted from the loss of hair cells in the base of the cochlea and a constant preoccupation with finding a treatment that protects against their toxic effects. A self-protection phenomenon to high ototoxic doses of gentamicin is proposed in this paper. Thirty-eight adult guinea pigs with normal hearing were tested using Preyer's reflex and the distortion product otoacoustic emission (DPOAE) test, and their cochleae were analyzed by scanning electron microscopy. To the four groups investigated, group I (control) and group II (low dose, 10 mg/kg/day for 30 days) showed a normal DPOEA and normal outer hair cells; group III (high dose, 160 mg/kg/day for 10 days) showed the absence of DPOEA and damage to the outer hair cells; and group IV (low dose, 10 mg/kg/day for 30 days followed by a high dose of 160 mg/kg/day for 10 days) showed a normal DPOEA and normal outer hair cells. These results demonstrate that there was a considerable self-protection phenomenon by gentamicin.
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Sao Paulo, Brazil.
authors.forename: Eloisa Nogueira
authors.initials: EN
authors.lastname: Maudonnet
authors.forename: José Antonio A
authors.initials: JA
authors.lastname: de Oliveira
authors.forename: Maria
authors.initials: M
authors.lastname: Rossato
authors.forename: Miguel Angelo
authors.initials: MA
authors.lastname: Hyppolito
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D003051:Cochlea / Q000187:drug effects* / Q000503:physiopathology / Q000648:ultrastructure; D015834:Cochlear Diseases / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D019610:Cytoprotection; D004305:Dose-Response Relationship, Drug; D005839:Gentamicins / Q000633:toxicity*; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects; D008855:Microscopy, Electron, Scanning; D017084:Otoacoustic Emissions, Spontaneous / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins