Objective: To investigate the hearing protection outcomes of different drug-eluting analog electrode arrays implanted into guinea pig cochleae.
Methods: Sixty guinea pigs were randomly divided into a negative control group and five experimental groups implanted separately with blank (drug carrier), dexamethasone (DXM), aracytine (Ara-C), Ara-C+DXM, and nicotinamide adenine dinucleotide (NAD+) eluting analog electrode arrays. Micro CT was used to supervise the surgical procedure. Auditory brainstem response (ABR) thresholds of the guinea pigs were measured and analyzed.
Results and Conclusions: Compared with the negative control, all other groups showed a significant increase in ABR threshold (p< 0.001) after surgery. Among them, there was no obvious difference between the blank (0 vs 90 days: 59.70± 10.57 vs 64.60± 9.47 dB SPL) and the NAD+ group (0 vs 90 days: 59.90± 9.87 vs 64.70± 8.65 dB SPL). On the other hand, the ABR thresholds in the DXM (0 days: 58.10± 10.73 dB SPL; 90 days: 51.70± 9.07 dB SPL) and the Ara-C group (0 days: 59.00± 10.05 dB SPL; 90 days: 51.60± 8.48 dB SPL) decreased significantly compared with the former two groups (p< 0.001). However, the Ara-C+DXM group showed no further benefit (p> 0.05). In addition, a significantly higher survival rate of spiral ganglion neurons in cochleae was observed in the Ara-C and/or DXM groups.
Keywords: guinea pig, cochlear implant, drug-eluting electrode, hearing protection