Efficiency of antioxidant Avenanthramide-C on high-dose methotrexate-induced ototoxicity in mice

PLoS One. 2022 Mar 30;17(3):e0266108. doi: 10.1371/journal.pone.0266108. eCollection 2022.

Abstract

Methotrexate (MTX) has been used in treating various types of cancers but can also cause damage to normal organs and cell types. Folinic acid (FA) is a well-known MTX antidote that protects against toxicity caused by the drug and has been used for decades. Since hearing loss caused by MTX treatment is not well studied, herein we aimed to investigate the efficiency of the antioxidant Avenanthramide-C (AVN-C) on high-dose MTX (HDMTX) toxicity in the ear and provide insights into the possible mechanism involved in MTX-induced hearing loss in normal adult C57Bl/6 mice and HEI-OC1 cells. Our results show that the levels of MTX increased in the serum and perilymph 30 minutes after systemic administration. MTX increased hearing thresholds in mice, whereas AVN-C and FA preserved hearing within the normal range. MTX also caused a decrease in wave I amplitude, while AVN-C and FA maintained it at higher levels. MTX considerably damaged the cochlear synapses and neuronal integrity, and both AVN-C and FA rescued the synapses. MTX reduced the cell viability and increased the reactive oxygen species (ROS) level in HEI-OC1 cells, but AVN-C and FA reversed these changes. Apoptosis- and ROS-related genes were significantly upregulated in MTX-treated HEI-OC1 cells; however, they were downregulated by AVN-C and FA treatment. We show that MTX can cause severe hearing loss; it can cross the blood-labyrinth barrier and cause damage to the cochlear neurons and outer hair cells (OHCs). The antioxidant AVN-C exerts a strong protective effect against MTX-induced ototoxicity and preserved the inner ear structures (synapses, neurons, and OHCs) from MTX-induced damage. The mechanism of AVN-C against MTX suggests that ROS is involved in HDMTX-induced ototoxicity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology
  • Apoptosis
  • Cell Line
  • Cisplatin / pharmacology
  • Hearing Loss* / chemically induced
  • Hearing Loss* / prevention & control
  • Methotrexate / toxicity
  • Mice
  • Ototoxicity* / etiology
  • Reactive Oxygen Species / metabolism
  • ortho-Aminobenzoates

Substances

  • Antioxidants
  • Reactive Oxygen Species
  • ortho-Aminobenzoates
  • avenanthramide-2C
  • Cisplatin
  • Methotrexate

Grants and funding

This research was supported by a grant (NRF-2020R1A2C1007473) from the Basic Science Research Program through the National Research Foundation of Korea, funded by the Ministry of Education, Science and Technology. It was also supported by a grant from the Chonnam National University Hospital Biomedical Research Institute (BCRI20038). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.