Cochlear protection by local insulin-like growth factor-1 application using biodegradable hydrogel

Area of Science:

• Oto-neuroscience
• Regenerative Medicine
• Biomaterials

Background:

• Noise-induced hearing loss (NIHL) is a significant sensory deficit.
• Cochlear hair cell damage is a primary cause of NIHL.
• Therapeutic strategies to protect cochlear structures are needed.

Purpose of the Study:

• To evaluate the protective effects of local recombinant human insulin-like growth factor-1 (rhIGF-1) delivery.
• To assess rhIGF-1 efficacy when applied via a biodegradable hydrogel to the cochlea.
• To investigate rhIGF-1's potential in preventing noise trauma-induced cochlear damage.

Main Methods:

• rhIGF-1-loaded hydrogel applied to the round window membrane in Sprague-Dawley rats.
• Control group received hydrogel with saline.
• Animals exposed to 120 dB white noise for 2 hours.
• Auditory brainstem responses (ABRs) measured at 8, 16, and 32 kHz.
• Hair cell loss quantified 7 and 30 days post-exposure.

Main Results:

• Local rhIGF-1 treatment significantly reduced ABR threshold elevations at 7 and 30 days post-noise exposure.
• Histological analysis confirmed significant preservation of outer hair cells in the rhIGF-1 treated group.
• rhIGF-1 demonstrated a protective effect against noise-induced cochlear damage.

Conclusions:

• Local application of rhIGF-1 via a biodegradable hydrogel is a promising therapeutic approach.
• This method offers potential for protecting the cochlea against noise trauma.
• Further research into IGF-1-based therapies for hearing preservation is warranted.