# Baicalin attenuates cisplatin-induced cochlear hair cell damage by modulating the ROS-p38 MAPK signaling pathway

## TL;DR

Baicalin protects against hearing loss caused by cisplatin by reducing oxidative stress and inhibiting a key signaling pathway.

## Contribution

This study identifies baicalin as a novel otoprotective agent targeting the ROS-p38 MAPK pathway in cisplatin-induced hearing loss.

## Key findings

- Baicalin mitigates cisplatin-induced hearing loss in mice by preserving cochlear hair cell integrity.
- Baicalin reduces mitochondrial ROS accumulation and prevents p38 MAPK activation in auditory cells.
- The protective effect of baicalin is reversed by p38 MAPK activation and mimicked by its inhibition.

## Abstract

Cisplatin-induced ototoxicity remains a major clinical challenge in chemotherapy, with limited pharmacological strategies available to prevent auditory damage. In this study, we explored the protective potential of baicalin, a flavonoid compound, against cisplatin-triggered cochlear injury.

In vivo, baicalin was administered to C57BL/6 mice prior to cisplatin treatment. Auditory function was assessed using auditory brainstem response (ABR) and distortion product otoacoustic emission measurements, and cochlear hair cell integrity was examined. In vitro, both House Ear Institute-Organ of Corti 1 (HEI-OC1) auditory cells and cochlear explants were used. Cell viability, apoptosis, mitochondrial reactive oxygen species (ROS) accumulation, and mitochondrial membrane potential (ΔΨm) were evaluated using MitoSOX Red, TMRM, and JC-1 fluorescence probes. The involvement of the p38 MAPK pathway was investigated using anisomycin (an activator) and SB203580 (an inhibitor) at the protein level.

In vivo, baicalin administration significantly mitigated cisplatin-induced hearing loss, as evidenced by improved ABR and distortion product otoacoustic emission thresholds and preserved cochlear outer hair cell structural and functional integrity. In vitro, baicalin pretreatment significantly improved cell viability and attenuated cisplatin-induced apoptosis. Mechanistically, baicalin markedly reduced mitochondrial ROS accumulation and maintained ΔΨm. Furthermore, baicalin pretreatment effectively inhibited p38 MAPK activation; this protective effect was reversed by anisomycin and mimicked by SB203580.

Collectively, these findings demonstrate that baicalin provides robust otoprotection against cisplatin-induced hearing loss. In vitro studies further indicate that this protective effect is associated with the attenuation of oxidative stress, maintenance of mitochondrial integrity, and inhibition of p38 MAPK–mediated apoptosis. Together, the results highlight baicalin as a promising candidate for therapeutic intervention against cisplatin-induced hearing loss.