Measurement of hydroxyl radical and 8-OHdG induced by heavy-ion irradiation

Abstract

(Purpose)
In order to quantitatively evaluate the generation of hydroxyl radicals in water and oxidative DNA damage caused by high LET radiation, we measured the ESR spectrum of DMPO radical adduct and 8-hydroxydeoxyguanosine (8-OHdG) in the salmon sperm DNA after irradiation.
(Materials and methods)
Pure water containing DMPO (200mM) and that containing salmon sperm DNA (1.0mg/ml) were irradiatied at a dose of 20Gy and 10Gy, respectively, with 290 MeV carbon-ion, 135 MeV carbon-ion and 490 MeV Silicon-ion beams at 4 and 37C. In addition, the sample was deoxygenized by argon to investigate the effect of oxygen on the OH generation. The DMPO solution was analyzed by ESR spectrometer 10 min fter irradiation. The 8-OHdG level in the ST-DNA were measured by HPLC with an electrochemical detector (ECD).
(Results)
Both levels of OH and 8-OHdG decreased as LET value increased. They were interfered with the temperature and the existence of oxygen during the irradiation.