Hyperbaric oxygenation with corticoid in experimental acoustic trauma.
Among possible therapies after acute acoustic trauma, hyperbaric oxygenation (HBO) combined with corticoid was found effective in several animal studies. Such evidence was obtained for moderate 20-25 dB losses. The aim of this study was to further assess this therapy for noise-induced hearing losses greater than previously examined. Sixty-five ears from thirty-six adult guinea pigs were used. Acoustically evoked responses from intracranial electrodes chronically implanted bilaterally into the ventral cochlear nucleus were used to assess acoustic sensitivity alterations. Trauma sound was a third-octave noise-band around 8 kHz presented bilaterally at 115 dB SPL for 45 min. One control group received no treatment, one group was treated with HBO only and another with corticoid only both starting within one day post-trauma, two groups were treated with both HBO and corticoid starting for one group within one day post-trauma, and for the second group at 6 days post-trauma. Acoustic thresholds were measured between the 6th and the 16th days after acoustic trauma. Animals treated with HBO alone or corticoid alone did not differ from controls. Combined HBO and corticoid therapy provided significant protection from noise-induced loss of auditory thresholds, especially when started one day post-exposure. Hearing loss reduction induced by HBO combined with corticoid was of similar magnitude (about 10-15 dB) as in previous studies although the induced hearing loss was considerably greater (about 40 dB instead of 20-25 dB).
Fakhry
Nicolas
N
Laboratoire de physiopathologie et actions thérapeutiques des gaz sous pression, EA 3280, Université de la Méditerranée and IMNSSA, Faculté de Médecine Nord, Boulevard P Dramard, 13916 Marseille Cedex 20, France.
Rostain
Jean Claude
JC
Cazals
Yves
Y
D000818:Animals; D001309:Auditory Threshold / Q000187:drug effects; D017626:Cochlear Nucleus / Q000187:drug effects* / Q000503:physiopathology; D003131:Combined Modality Therapy; D004195:Disease Models, Animal; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology* / Q000627:therapeutic use; D006168:Guinea Pigs; D006317:Hearing Loss, Noise-Induced / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D006931:Hyperbaric Oxygenation; D008776:Methylprednisolone Hemisuccinate / Q000494:pharmacology* / Q000627:therapeutic use; D009622:Noise / Q000009:adverse effects; D013997:Time Factors
D005938:Glucocorticoids; D008776:Methylprednisolone Hemisuccinate