薬物の蝸牛におよぼす影響に関する実験的研究

音響外傷ならびに薬物鼓室内投与における問題を中心に

抄録

The effect of methyl B₁₂ on cochlear injury after noise exposure and that of topical antibiotics on cochlear function were examined.
I. Forty-five albino guinea pigs were exposed to white noise of 100dB SPL for 2.5 hours, and 27 of the animals with temporary threshold shift (NITTS) were treated with methylcobalamin (methyl B₁₂) in doses of 500/μg/kg for two weeks. Animals were killed at various intervals up to two weeks following acoustic stimulation. Cochlear morphology and function were evaluated by scanning electron microscope (SEM) and auditory brain stem response (ABR). The efficiency of methyl B₁₂ for both functional and morphological recovery from cochlear damage was proved.
II. Nineteen albino guinea pigs were given intratympanic antibiotics or isotonic saline: 7 received gentamicin, 9 cefsulodin and 3 isotonic sodium chloride (control group). Cefsulodin sodium solution (600mg/kg), gentamicin solution (30mg/kg) and iso-tonic sodium chloride solution 0.2ml were instilled into the tympanic cavity through a silicon tube in the retroauricular region for 4 days.
There was no decrease in audioresponses (ECoG-threshold) or cochlear injury on SEM in the cefsulodin or control groups, but audioresponses were markedly disturbed in the gentamicin group.