Hyperbaric Oxygen Treatment Improves Hearing Level via Attenuating TLR4/NF-κB Mediated Inflammation in Sudden Sensorineural Hearing Loss Patients

Abstract

Objective: Hyperbaric oxygen treatment (HBOT) has demonstrated efficacy in improving hearing levels of patients with idiopathic sudden sensorineural hearing loss (ISSHL); however, the underlying mechanisms are not well understood. HBOT alleviates the inflammatory response, which is mediated by Toll-like receptor (TLR) 4 and nuclear factor (NF)-κB. In this study we investigated whether HBOT attenuates inflammation in ISHHL patients via alteration of TLR4 and NF-κB expression.

Methods: ISHHL patients ( n = 120) and healthy control subjects ( n = 20) were enrolled in this study. Patients were randomly divided into medicine group treated with medicine only ( n = 60) and HBO group receiving both HBOT and medicine ( n = 60). Audiometric testing was performed pre- and post-treatment. TLR4, NF-кB, and TNF-α expression in peripheral blood of ISSHL patients and healthy control subjects was assessed by ELISA before and after treatment.

Results: TLR4, NF-κB, and TNF-α levels were upregulated in ISSHL patients relative to healthy control subjects; the levels were decreased following treatment and were lower in the HBO group than that in the medicine group post-treatment ( P < 0.05 and P < 0.01).

Conclusion: HBOT alleviates hearing loss in ISSHL patients by suppressing the inflammatory response induced by TLR4 and NF-κB signaling.

Keywords: Hyperbaric oxygen treatment; Nuclear factor-kB; Sudden sensorineural hearing loss; Toll-like receptor 4.