Ventral approach to rat inner ear preserves cochlear function

Qiu, Jianxin; Olivius, Petri; Tong, Bu-shen; Borg, Erik; Duan, Maoli

doi:10.1080/00016480600818104

Cited by 6 publications

(8 citation statements)

References 17 publications

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“…The mechanism underlying noise induced threshold elevation and hearing recovery is closely related to IHC functions, especially cochlear synapse plasticity. Kujawa and Liberman showed that 2 h of 100 dB SPL noise (8)(9)(10)(11)(12)(13)(14)(15)(16) exposure killed half of IHC/auditory nerve synapses in high-frequency regions permanently but sensitivity to quiet sounds was easy to recover [6]. Although their research focused on the acute noise stress, the conclusion was consistent with our findings.…”

Section: Discussionsupporting

confidence: 90%

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Hidden hearing loss is associated with loss of ribbon synapses of cochlea inner hair cells

et al. 2021

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This study aimed to observe the changes in the cochlea ribbon synapses after repeated exposure to moderate-to-high intensity noise. Guinea pigs received 95 dB SPL white noise exposure 4 hours a day for consecutive 7 days (we regarded it a medium-term and moderate-intensity noise, or MTMI noise). Animals were divided into 4 groups: Control, 1DPN (1-day post noise), 1WPN (1-week post noise), and 1MPN (1-month post noise). Auditory function analysis by ABR and CAP recordings, as well as ribbon synapse morphological analyses by immunohistochemistry (Ctbp2 and PSD95 staining) were performed one day, one week, and one month after noise exposure. After MTMI noise exposure, the amplitudes of auditory brainstem response (ABR) I and III waves were suppressed. The compound action potential (CAP) threshold was elevated, and CAP amplitude was reduced in the 1DPN group. No apparent changes in hair cell shape, arrangement or number were observed, but the number of ribbon synapse was reduced. The 1WPN and 1MPN groups showed that part of ABR and CAP changes recovered, as well as the synapse number. The defects in cochlea auditory function and synapse changes were observed mainly in the high-frequency region. Together, repeated exposure in MTMI noise can cause hidden hearing loss, which is partially reversible after leaving the noise environment; and MTMI noise induced hidden hearing loss is associated with inner hair cell ribbon synapses.

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Section: Discussionsupporting

confidence: 90%

“…The auditory brainstem response (ABR) threshold measurement and compound action potential (CAP) response measurement were two commonly used tests for cochlear function assessment [9][10][11][12]. Animals under ABR and CAP tests were anaesthetized with pentobarbital sodium (30m/Kg) and maintained body temperature at 37.5~38.0℃.…”

Section: Auditory Function Testsmentioning

confidence: 99%

Hidden hearing loss is associated with loss of ribbon synapses of cochlea inner hair cells

et al. 2021

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“…A ventral surgical approach was performed to gain access to the rat round window, following and adapting previously published procedures. 7,8,10,19 We confirmed that this surgical approach preserves auditory function, as assessed by ABR evaluation, and cochlear morphology, and that it is associated with low rates of morbidity and mortality. Most clinical studies involving direct round window administration have been performed with gentamicin, due to its ready pharmacological availability and vestibulotoxic rather than cochleotoxic effects.…”

Section: Discussionsupporting

confidence: 72%

“…5,6 Therefore, the ventral approach is likely to be a more conservative surgical procedure in this species. 7,8 However, transtympanic administration of ototoxic drugs without delivery systems does not ensure that reproducible doses reach the round window, and usually multiple injections are required to induce measurable damage. 9 The use of vehicles such as gelatin or fibrin sponges placed on the round window should provide more reproducible patterns of damage.…”

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confidence: 99%

Direct drug application to the round window: A comparative study of ototoxicity in rats

Murillo-Cuesta

García-Alcántara

Sánchez

et al. 2009

Otolaryngol.--head neck surg.

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Objective: To assess the validity of inducing ototoxicity in rats by applying a sponge soaked in kanamycin and furosemide on the round window. Study Design: Basic, randomized, nonblind experimental study. Setting: Animal models of cochlear damage and reliable methods of local drug delivery are fundamental to study hearing loss and to design new therapies. Subjects and Methods: Four experimental groups of six Wistar rats with different methods of drug administration were used: (1) injection of subcutaneous kanamycin (400 mg/kg) and intravenous furosemide (100 mg/kg); (2) local application of a sponge soaked in saline close to the round window; (3) animals for which the sponge was soaked in a solution containing kanamycin (200 mg/mL) and furosemide (50 mg/mL); and (4) sham-operated rats. The tympanic bulla was exposed using a ventral approach, and a bullostomy was performed to visualize the round window membrane. Cochlear function was assessed by measuring the auditory brainstem response, and hearing thresholds in response to click and tone burst stimuli were determined as peak and interpeak latencies. At the end of the study, cochlear histology was analyzed. Results: Systemic administration of kanamycin and furosemide induced profound hearing loss and severe hair cell damage. Local delivery of these ototoxic drugs caused comparable damage but avoided the systemic side effects of the drug. Sham-operated and saline control animals did not experience functional alterations. Conclusion: Situating a sponge soaked in kanamycin and furosemide on the round window membrane through the ventral approach is a reliable method to provoke local ototoxicity in rats.

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“…In addition to selective targeting, it is necessary to develop a vector delivery method that provides safer and more efficient results [8,[15][16][17]. Viral vectors can be injected directly by punching a hole in the side wall of the cochlea [15].…”

Section: Discussionmentioning

confidence: 99%

Efficient transduction of spiral ganglion cells using adenovirus type 5 vector in the rat

Li¹,

Han²

2010

Acta Oto-Laryngologica

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Ventral approach to rat inner ear preserves cochlear function

Abstract: The ventral approach enabled the direct visualization of the tympanic bulla. Thus, the tympanic bulla could be easily opened in a manner that was benign to cochlear function. There was no significant difference in ABR threshold before and after surgery.

Cited by 6 publications

References 17 publications

Hidden hearing loss is associated with loss of ribbon synapses of cochlea inner hair cells

Hidden hearing loss is associated with loss of ribbon synapses of cochlea inner hair cells

Direct drug application to the round window: A comparative study of ototoxicity in rats

Efficient transduction of spiral ganglion cells using adenovirus type 5 vector in the rat

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