Molecular hydrogen attenuates radiation-induced nucleobase damage to DNA in aerated aqueous solutions

作者：Abou Hamdan Mhamad; Gardette Bernard; Cadet Jean; Gharib Bouchra; De Reggi Max^*; Douki Thierry; Triantaphylides Christian

来源：International Journal of Radiation Biology, 2016, 92(9): 536-541.

DOI：10.1080/09553002.2016.1206234

• DNA base oxidation
• hydroxyl radical scavenging
• molecular hydrogen-mediated protection
• oxidized 2 '-deoxyribonucleosides

Purpose: The main aim of the present study is to gain mechanistic insights into the modulating effect of molecular hydrogen on the -radiation-induced alteration pathways of DNA nucleobases.Materials and methods: Aerated aqueous solutions of calf thymus DNA were exposed to a Co-60 source at doses ranging from 0 to 55Gy under normoxic conditions, in the presence or not of 0.7MPa hydrogen or helium. The measurement of several modified bases was performed using HPLC associated with electrospray ionization tandem pass spectrometry (HPLC-ESI-MS/MS). Bleaching of aqueous solutions of p-nitrosodimethylaniline (p-NDA) solutions was also used to allow the quantification of hydroxyl radical (center dot OH) formation.Results:pNDA bleaching was significantly reduced in the presence of hyperbaric hydrogen. This is undoubtedly due to (OH)-O-center dot scavenging by H-2 since, under the same conditions, He had no effect. Similarly, base alterations were significantly reduced in the presence of hydrogen, as compared to controls under normal atmosphere or in the presence of helium. The relative proportions of modified nucleobases were not changed, showing that the only effect of H-2 is to scavenge (OH)-O-center dot without exhibiting reducing properties.Conclusions: Our findings demonstrate that H-2 exerts a significant protection against radiation-induced DNA base damage in aqueous solutions, (OH)-O-center dot scavenging being the only mechanism involved.

• 出版日期2016
• 单位中国地震局