Non-thermal plasma-induced DMPO-OH yields hydrogen peroxide

Yasumasa Okazaki; Hiromasa Tanaka; Ken-Ichiro Matsumoto; Masaru Hori; Shinya Toyokuni

doi:10.1016/j.abb.2021.108901

Non-thermal plasma-induced DMPO-OH yields hydrogen peroxide

Arch Biochem Biophys. 2021 Jul 15:705:108901. doi: 10.1016/j.abb.2021.108901. Epub 2021 May 6.

Authors

Yasumasa Okazaki¹, Hiromasa Tanaka², Ken-Ichiro Matsumoto³, Masaru Hori⁴, Shinya Toyokuni⁵

Affiliations

¹ Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Showa-Ku, Nagoya, 466-8550, Japan. Electronic address: samasuya@med.nagoya-u.ac.jp.
² Center for Low-temperature Plasma Sciences, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan; Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Showa-Ku, Nagoya, 466-8550, Japan.
³ Quantitative RedOx Sensing Group, Department of Radiation Regulatory Science Research, National Institute of Radiological Sciences, Quantum Life and Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan.
⁴ Center for Low-temperature Plasma Sciences, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan.
⁵ Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Showa-Ku, Nagoya, 466-8550, Japan; Center for Low-temperature Plasma Sciences, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan. Electronic address: toyokuni@med.nagoya-u.ac.jp.

PMID: 33964248
DOI: 10.1016/j.abb.2021.108901

Abstract

Recent developments in electronics have enabled the medical applications of non-thermal plasma (NTP), which elicits reactive oxygen species (ROS) and reactive nitrogen species (RNS), such as hydroxyl radical (^●OH), hydrogen peroxide (H₂O₂), singlet oxygen (¹O₂), superoxide (O₂^●-), ozone, and nitric oxide at near-physiological temperatures. In preclinical studies or human clinical trials, NTP promotes blood coagulation, eradication of bacterial, viral and biofilm-related infections, wound healing, and cancer cell death. To elucidate the solution-phase biological effects of NTP in the presence of biocompatible reducing agents, we employed electron paramagnetic resonance (EPR) spectroscopy to quantify ^●OH using a spin-trapping probe, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO); ¹O₂ using a fluorescent probe; and O₂^●- and H₂O₂ using luminescent probes in the presence of thiols or tempol. NTP-induced ^●OH was significantly scavenged by dithiothreitol (DTT), reduced glutathione (GSH), and oxidized glutathione (GSSG) in 2 or 5 mM DMPO. NTP-induced O₂^●- was significantly scavenged by 10 μM DTT and GSH, while ¹O₂ was not efficiently scavenged by these compounds. GSSG degraded H₂O₂ more effectively than GSH and DTT, suggesting that the disulfide bonds reacted with H₂O₂. In the presence of 1-50 mM DMPO, NTP-induced H₂O₂ quantities were unchanged. The inhibitory effect of tempol concentration (50 and 100 μM) on H₂O₂ production was observed in 1 and 10 mM DMPO, whereas it became ineffective in 50 mM DMPO. Furthermore, DMPO-OH did not interact with tempol. These results suggest that DMPO and tempol react competitively with O₂^●-. Further studies are warranted to elucidate the interaction between NTP-induced ROS and biomolecules.

Keywords: DMPO; Dithiothreitol; Electron paramagnetic resonance (EPR); Glutathione; Hydrogen peroxide; Non-thermal plasma (NTP).

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cyclic N-Oxides / chemistry*
Electron Spin Resonance Spectroscopy
Hydrogen Peroxide / chemistry*
Hydroxyl Radical / chemistry
Plasma Gases / chemistry*

Substances

Cyclic N-Oxides
Plasma Gases
Hydroxyl Radical
2,2-dimethyl-5-hydroxy-1-pyrrolidinyloxy
Hydrogen Peroxide