Hany Amin Riad*

Professor, Benha University, Egypt

*Corresponding Author: Hany Amin Riad, Professor, Benha University, Egypt.

Received: May 16, 2025; Published: June 30, 2025

Abstract

Background: Sensorineural hearing loss (SNHL) affects hundreds of millions globally, often due to irreversible damage to cochlear hair cells or auditory nerve fibers. Systemic drug delivery is limited by poor intracochlear penetration and systemic side effects, prompting the development of localized delivery strategies.

Objective: This preclinical study evaluates and compares the efficacy of three localized drug delivery techniques—intratympanic dexamethasone (IT-Dex), cochlear implant-mediated sustained BDNF release (CI-Drug), and biodegradable gelatin hydrogel loaded with GDNF (Hydrogel-GDNF)—in preserving auditory function and promoting cochlear regeneration in a noise-induced hearing loss (NIHL) model in guinea pigs.

Methods: Sixty guinea pigs were randomly assigned to six groups (n = 10/group): IT-Dex, CI-Drug, Hydrogel-GDNF, systemic steroids, placebo, and untreated control. NIHL was induced via 110 dB SPL noise exposure for 2 hours. Auditory function was assessed using auditory brainstem response (ABR) at baseline and days 7, 14, and 03. Cochlear histology, inflammatory markers (IL-6, TNF-α), and tissue integrity were analyzed post-mortem.

Results: At 30 days post-treatment, CI-Drug showed the lowest ABR thresholds (28 ± 5 dB SPL) and highest hair cell survival (82%), followed by Hydrogel-GDNF (30 ± 4 dB SPL; 75%). Both localized neurotropic-based therapies significantly outperformed IT-Dex, systemic steroids, and placebo (p < 0.05). Systemic steroids showed minimal benefit over placebo. Localized delivery methods also reduced inflammation and tissue damage compared to systemic and placebo controls.

Conclusion: Localized drug delivery techniques, particularly sustained-release systems incorporating neurotrophic factors, offer superior cochlear protection and regenerative potential compared to systemic administration. These findings support further translational research into implantable and biodegradable delivery platforms for treating SNHL.

Keywords: Noise-Induced Hearing Loss (NIHL); Sensorineural Hearing Loss (SNHL)

References

1. Plontke SK., et al. Frontiers in Neurology 8 (2017): 86.
2. Salt A N., et al. Hearing Research 341 (2016): 155-164.
3. Farahmand Ghavi F., et al. Biomaterials , 243 (2020): 119931.
4. Shi X., et al. Acta Biomaterialia 88 (2019): 1-13.
5. Wan G., et al. Journal of Neuroscience22 (2014): 7513-7521.
6. Bas E., et al. Journal of Controlled Release 297 (2019): 24-35.
7. Liu Y., et al. Nature Communications1 (2021): 1-13.
8. Hessler R., et al. Otology and Neurotology2 (2022): e210-e218.

Citation

Citation: Hany Amin Riad. “Evaluating Efficacy of Localized Drug Delivery Techniques for Cochlear Protection and Regeneration".Acta Scientific Ophthalmology 8.7 (2025): 19-22.

Copyright

Copyright: © 2025 Hany Amin Riad. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.