Cisplatin is an effective chemotherapeutic drug. Its side effects, ototoxicity and genotoxicity, limit widespread application. Melatonin could reduce these toxic effects due to its antioxidant activity.

To determine the effect of melatonin against cisplatin-induced ototoxicity and genotoxicity in rats.

To assess ototoxicity, 33 rats were randomly divided into: group 1 (saline), group 2 (melatonin), group 3 (cisplatin + saline), and group 4 (cisplatin + melatonin). Groups 3 and 4 received a single dose of 10 mg/kg of cisplatin. Groups 2 and 4 received daily doses of 1 mg/kg of melatonin. The number of viable neurons and their average diameter in the spiral and vestibular ganglia were analyzed. In the stria vascularis and spiral ligament, the number of viable cells was evaluated. To assess genotoxicity, 12 animals were randomly divided into: group A (saline), group B (cisplatin + saline), and group C (cisplatin + melatonin). The rats in groups B and C received a single dose of 10 mg/kg of cisplatin. Group C received a single dose of 1 mg/kg of melatonin.

The micronucleus count and percentage of polychromatic erythrocytes in the bone marrow of rat femurs were analyzed. The animals in group 3 presented a greater loss of cells than the animals in other groups regarding all cochlear structures evaluated. Furthermore, the diameters of neurons were smaller in the animals in group 3. Melatonin-treated rats presented a lower micronucleus count and a higher number of polychromatic erythrocytes than animals treated with cisplatin alone.

Melatonin reduces cisplatin-induced cyto-histopathological damage in the bone marrow and inner ear; therefore, it could be used as a tumor adjuvant treatment.

The data that support the findings of the present study are available from the corresponding author upon reasonable request.

Received: 22 November 2024

Accepted: 24 March 2025

Article published online:
10 September 2025

© 2025. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution 4.0 International License, permitting copying and reproduction so long as the original work is given appropriate credit (https://creativecommons.org/licenses/by/4.0/)

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Bibliographical Record
Juliana Gusmão de Araujo, Lucieny Silva Martins Serra, Lucas Lauand, Selma Aparecida Souza Kückelhaus, André Luiz Lopes Sampaio. Melatonin Prevents Cisplatin-Induced Cyto-Histopathological Damage in the Bone Marrow and Inner Ear. Int Arch Otorhinolaryngol 2025; 29: s00451809645.
DOI: 10.1055/s-0045-1809645