Sarsasapogenin Protects Hair Cells from Cisplatin-Induced Ototoxicity by Attenuating Apoptosis and Ferroptosis via Alleviating Oxidative Stress

Zhifeng Chen^1,2,3Ting Xie⁴Chenyu Chen^1,5,6Tingting Lin⁷Xiaobo Wu^1,2Yuqing Chen^1,2Yanchun Lin^1,2Xiaoyang Luo^1,2Chaojun Zeng^1,8,9*Chang Lin^1,2,3*

• ¹Department of Otorhinolaryngology-Head and Neck Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
• ²Department of Otorhinolaryngology-Head and Neck Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
• ³Fujian Institute of Otolaryngology, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
• ⁴Department of Hepatopancreatobiliary Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
• ⁵ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China
• ⁶NHC Key Laboratory of Hearing Medicine Research, Eye & ENT Hospital, Fudan University, Shanghai, China
• ⁷University of Science and Technology of China, Hefei, China
• ⁸Department of Otolaryngology, Affiliated Hospital of Putian University, Putian, China
• ⁹Putian Institute of Otolaryngology, Affiliated Hospital of Putian University, Putian, China

Background and Purpose: Cisplatin is a widely used chemotherapy drug for the treatment of solid tumours, but its clinical benefit is often limited by ototoxicity, leading to irreversible sensorineural hearing loss. However, there is a lack of effective strategies to prevent hearing loss caused by cisplatin in adults, while sodium thiosulfate is approved by the Food and Drug Administration in the United States for only use at the pediatric level. Sarsasapogenin, a natural compound of the Anemarrhena asphodelides, has antioxidant and neuroprotective properties, which suggest that it may attenuate the ototoxicity induced by cisplatin. The aim of this study is to evaluate the otoprotective effects of sarsasapogenin and its underlying mechanism as a potential therapeutic intervention for the prevention of ototoxicity induced by cisplatin.Cell viability was assessed by CCK-8 and cell apoptosis was assessed by flow cytometry. Reactive oxygen species (ROS) levels and mitochondrial dysfunction were quantified by immunofluorescence. In addition, expression of the molecules involved in apoptosis and ferroptosis was analyzed by qRT-PCR and western blot. In vivo auditory function was evaluated by auditory brainstem response testing, and the survival of hair cells in the cochlea was quantified by immunolabeling with myosin-VIIa.Results: Sarsasapogenin significantly alleviated cisplatin-induced oxidative stress and restored mitochondrial function in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells. Furthermore, sarsasapogenin effectively protected against cisplatin-induced sensorineural hearing loss and hair cell degeneration in vivo. Mechanistically, the protective effects of sarsasapogenin were primarily mediated through the inhibition of apoptosis and ferroptosis, both in vitro and in vivo.This study provides compelling evidence for the otoprotective effects of sarsasapogenin, suggesting its potential as a therapeutic intervention to prevent cisplatin-induced hearing loss.