title: Protective Effect of Tempol against Cisplatin-Induced Ototoxicity.
abstract: One of the major adverse effects of cisplatin chemotherapy is hearing loss. Cisplatin-induced ototoxicity hampers treatment because it often necessitates dose reduction, which decreases cisplatin efficacy. This study was performed to investigate the effect of Tempol on cisplatin-induced ototoxicity in an auditory cell line, House Ear Institute-Organ of Corti 1 (HEI-OC1). Cultured HEI-OC1 cells were exposed to 30 μM cisplatin for 24 h with or without a 2 h pre-treatment with Tempol. Cell viability was determined using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and apoptotic cells were identified using terminal deoxynucleotidyl transferase dUTP nick end labeling of nuclei (TUNEL) assay and flow cytometry. The effects of Tempol on cisplatin-induced cleaved poly(ADP-ribose) polymerase, cleaved caspase, and mitochondrial inducible nitric oxide synthase expression were evaluated using western blot analysis. Levels of intracellular reactive oxygen species (ROS) were measured to assess the effects of Tempol on cisplatin-induced ROS accumulation. Mitochondria were evaluated by confocal microscopy, and the mitochondrial membrane potential was measured to investigate whether Tempol protected against cisplatin-induced mitochondrial dysfunction. Cisplatin treatment decreased cell viability, and increased apoptotic features and markers, ROS accumulation, and mitochondrial dysfunction. Tempol pre-treatment before cisplatin exposure significantly inhibited all these cisplatin-induced effects. These results demonstrate that Tempol inhibits cisplatin-induced cytotoxicity in HEI-OC1, and could play a preventive role against cisplatin-induced ototoxicity.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Chosun University School of Medicine, Gwangju 61453, Korea. threefold@hanmail.net.|Division of Natural Medical Science, Chosun University School of Medicine, Gwangju 61452, Korea. threefold@hanmail.net.
authors.forename: Cha Kyung
authors.initials: CK
authors.lastname: Youn
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Chosun University School of Medicine, Gwangju 61453, Korea. mdjunek@medimail.co.kr.
authors.forename: Jun
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Chosun University School of Medicine, Gwangju 61453, Korea. maria2046@hanmail.net.
authors.forename: Eu-Ri
authors.initials: ER
authors.lastname: Jo
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Chosun University School of Medicine, Gwangju 61453, Korea. way2ojay@naver.com.
authors.forename: Jeonghyun
authors.initials: J
authors.lastname: Oh
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Chosun University School of Medicine, Gwangju 61453, Korea. nydo@chosun.ac.kr.
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Do
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Chosun University School of Medicine, Gwangju 61453, Korea. chosi@chosun.ac.kr.
authors.forename: Sung Il
authors.initials: SI
authors.lastname: Cho
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000633:toxicity*; D003497:Cyclic N-Oxides / Q000494:pharmacology*; D005434:Flow Cytometry; D006198:Hair Cells, Auditory / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D018696:Neuroprotective Agents / Q000494:pharmacology; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013113:Spin Labels
chemical_list: D000970:Antineoplastic Agents; D003497:Cyclic N-Oxides; D018696:Neuroprotective Agents; D017382:Reactive Oxygen Species; D013113:Spin Labels; D052247:Nitric Oxide Synthase Type II; D011065:Poly(ADP-ribose) Polymerases; D053148:Caspase 3; D002945:Cisplatin; C001803:tempol
keywords: Tempol; apoptosis; cell death; cisplatin; ototoxicity