목적: Cochlear implantation (CI) is widely performed for patients with severe hearing loss. However, trauma, inflammation, and fibrosis induced by CI surgery can lead to residual hearing loss. This study aimed to evaluate the protective effects of dexamethasone alone, a combination of dexamethasone and N-acetylcysteine (NAC), and a combination of dexamethasone and glial cell line-derived neurotrophic factor (GDNF) in preserving residual hearing after CI. 방법:Guinea pig models were used, and electrode needles coated with each drug were implanted into the left cochlea via the round window approach. Auditory brainstem responses (ABR) were measured before surgery as a pre-operative assessment. Post-operatively, ABR measurements were conducted one week and one month after surgery. The cochleae were harvested at both time points, and qRT-PCR was performed to assess the expression of TNF-α, NOS2, IL-1β, and IL-6. Additionally, hematoxylin and eosin (H&E) staining was conducted on cochlear tissues collected one month after surgery to evaluate inflammation and fibrosis. 결과:The ABR results showed a tendency for hearing preservation in guinea pigs treated with the combination of dexamethasone and NAC or dexamethasone and GDNF at 1 week post-surgery, with a more pronounced effect in the group treated with dexamethasone and NAC at 1 month post-surgery. qRT-PCR analysis demonstrated a significant reduction in the expression of TNF- α, IL-1β, and IL-6 in guinea pigs treated with dexamethasone compared to the untreated control group. H&E staining revealed that guinea pigs treated with dexamethasone exhibited reduced inflammation and fibrosis compared to the control group. 결론:This study suggests that a combination of dexamethasone with NAC or GDNF can effectively suppress inflammation and fibrosis, thereby mitigating hearing loss after CI. These findings highlight the potential of combination drug therapies as a novel strategy for preserving residual hearing following CI surgery.