title: Efficacy of intratympanic methylprednisolone acetate in treatment of drill-induced sensorineural hearing loss in guinea pigs.
abstract: Intratympanic steroids offer direct access to the inner ear with high concentration and without systemic effects. In this study, the efficacy of intratympanic methylprednisolone acetate (IT-MPA) was evaluated in a guinea-pig model of drill-induced inner ear trauma. Twenty-five guinea pigs were divided into a control group to document the baseline distortion product otoacoustic emissions (DPOAEs) and the normal scanning electron microscopic (SEM) morphology of the inner ear. The animals in the study group were subdivided into a steroid-only group (S), a trauma-only group (T), a trauma-plus-time group (TT), and a trauma-plus-steroid (TS) group. IT-MPA was found to have no damaging effect on the inner ear. Twelve days after trauma, there was spontaneous although incomplete recovery of the DPOAEs amplitudes and SEM morphology with scar tissue replacing lost outer hair cells. Statistically higher DPOAEs amplitudes (p < 0.05) were recorded in the TS group that had nearly normal SEM morphology compared to the TT group. The authors conclude that IT-MPA significantly improves drill-induced sensorineural hearing loss and inner ear morphological changes in guinea pigs.
authors.affiliation: Otorhinolaryngology Department, Suez Canal University, Ismailia, Egypt. Dhennawi@yahoo.com
authors.forename: Diaa M
authors.initials: DM
authors.lastname: El-Hennawi
authors.forename: Mohamed H Badr
authors.initials: MH
authors.lastname: El-Deen
authors.forename: Ashraf S
authors.initials: AS
authors.lastname: Abou-Halawa
authors.forename: Hani S
authors.initials: HS
authors.lastname: Nadeem
authors.forename: Mohamed R
authors.initials: MR
authors.lastname: Ahmed
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D003051:Cochlea / Q000473:pathology*; D004333:Drug Administration Routes; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005260:Female; D006168:Guinea Pigs; D006199:Hair Cells, Auditory, Inner / Q000473:pathology; D018072:Hair Cells, Auditory, Outer / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D000077555:Methylprednisolone Acetate; D008855:Microscopy, Electron, Scanning / Q000379:methods; D023421:Models, Animal; D009622:Noise; D009925:Organ of Corti / Q000473:pathology; D017084:Otoacoustic Emissions, Spontaneous; D014432:Tympanic Membrane
chemical_list: D000893:Anti-Inflammatory Agents; D000077555:Methylprednisolone Acetate; D008775:Methylprednisolone