Effect of Growth Factors on Hearing Restoration in Deafened Animal Model / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Sensorineural hearing loss is caused by ototoxic drugs, radiation therapy, noise exposure and trauma, etc. They make irreversible changes in cochlear hair cells and degeneration of spiral ganglion neurons. It is known that neurotrophins and other growth factors have an important role in protectingcochlear hair cells and spiral ganglion neurons. We designed this study to analyze the effect of neurotrophins and growth factors delivered to the inner ear of deafened guinea pig. MATERIALS AND METHOD: Healthy 15 guinea pigs with normal Preyer's reflex were chosen, and were made deaf by infusion of kanamycin and ethacrynic acid. Myringotomy was done to both ears, normal saline injected into the left ear, and BDNF (brainderived neurotrophic factor), GDNF (glial cell derived neurotrophic factor), NT-3 (neurotrophin-3), IGF (insulin-like growth factor), EGF (epidermal growth factor), FGF (fibroblast growth factor) were injected in the right ear. RESULTS: Statistically significant hearing gain was obtained up to 35.00+/-13.78 dB in the group 1 (BDNF, GDNF, NT-3 treated group), and up to 34.0+/-5.47 dB in the group 2 (IGF treated group). However, no statistically significant hearing gain was observed in the group 3 (EGF, FGF treated group). CONCLUSION: We observed statistically important improvement of hearing threshold in the BDNF, GDNF, NT-3 treated group and IGF treated group.