Assessment of the efficacy of a local steroid rescue treatment administered 2 days after a moderate noise-induced trauma in guinea pig

Abstract

Objectives: Intratympanic injection of corticosteroids membrane after noise-induced hearing loss is an accepted alternative to general administration. We investigated the effect on hearing of a hyaluronic acid gel with liposomes loaded with dexamethasone (DexP) administered into the middle ear.

Methods: An acute acoustic trauma was performed to 13 guinea pigs for a period of 1 h on Day −2. Two 2 days after the noise trauma, the animals were then assigned randomly to four experimental groups: control without gel, gel injection, gel-containing free DexP, gel-containing DexP loaded into liposomes. Auditory thresholds were measured with Auditory Brainstem Response before Day −2 and at Day 0, Day 7 and Day 30 after noise trauma.

Results: Seven days after, a complete hearing recovery was observed in the control group at all frequencies apart from 8 kHz, and no recovery was observed in the three groups receiving a gel injection. Thirty days after trauma, all of the animals had recovered normal hearing, apart from at the 8-kHz frequency, with similar auditory thresholds.

Conclusions: Local DexP administration 48 h after a mild acoustic trauma did not improve hearing recovery, even with a sustained release in a specific gel formulation designed for inner ear therapy.

Chinese abstract

目的：在噪音诱发的听力损失之后, 鼓室内注射皮质类固醇膜是常规用药的可接受替代方案。我们调查了注射中耳的含予地塞米松（DexP）的脂质体透明质酸凝胶对听力的影响。

方法：在第2天对13只豚鼠进行1小时的剧烈听觉创伤。在噪声创伤2天后, 将动物随机分为四个实验组：没有凝胶的对照组、凝胶注射组、含凝胶的游离DexP组、含凝胶的DexP加载到脂质体组。在第-2天之前以及在第0天、第7天和第30天之后, 用“听觉脑干反应”测量听觉阈值。

结果：7天以后, 对照组除8kHz以外的所有频率均观察到完全听力恢复, 而在接受凝胶注射的三组中没有观察到恢复。创伤后30天, 除8kHz频率外, 所有动物的听力都恢复正常, 都具有相似的听觉阈值。

结论：即使有在为内耳治疗设计的特定凝胶制剂中的持续释放, 轻度听觉创伤48小时后局部DexP给药也不能改善听力恢复。

Keywords:

• Dexamethasone phosphate
• guinea pigs
• hearing loss
• noise-induced
• hydrogel
• liposomes

Acknowledgements

This research was supported by Fondation pour la Recherche Médicale, Association des Anciens Internes des Hôpitaux de Paris, INSERM and UPMC.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by Fondation pour la Recherche Médicale, Association des Anciens Internes des Hôpitaux de Paris, INSERM and UPMC.