Electron spin resonance studies of free radicals in gamma-irradiated golden hamster embryo cells: radical formation at 77 and 295 K, and radioprotective effects of vitamin C at 295 K.
Formation of free radicals in golden hamster embryo (GHE) cells produced by gamma irradiation at 77 and 295 K has been studied by electron spin resonance (ESR) spectroscopy. The yields of free radicals in the gamma-irradiated frozen cells at 77 K increase linearly with increasing dose in the range from 8 Gy to 1.3 kGy, suggesting that the mechanism of radical formation at a dose of 8 Gy is the same as that at 1.3 kGy. When GHE cells are irradiated with 5 kGy gamma rays at 295 K and then the ESR spectrum is measured at 77 K, a part of the organic radicals produced can be observed clearly. The organic radicals survive in GHE cells for more than 24 h at room temperature. The formation of the organic radicals by gamma irradiation is suppressed upon the addition of vitamin C to the GHE cells. When an aqueous solution of albumin (0.1 kg dm-3) is gamma-irradiated with 5 kGy at 295 K, albumin radicals are observed by ESR. The formation of the albumin radicals is suppressed drastically upon the addition of vitamin C. The efficient radioprotection of vitamin C against radical formation has been interpreted in terms of the scavenging of albumin radicals by vitamin C.
Yoshimura
T
T
Department of Applied Chemistry, Faculty of Engineering, Nagoya University, Japan.
Matsuno
K
K
Miyazaki
T
T
Suzuki
K
K
Watanabe
M
M
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D002460:Cell Line; D006224:Cricetinae; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D004578:Electron Spin Resonance Spectroscopy; D004622:Embryo, Mammalian / Q000737:chemistry / Q000187:drug effects / Q000528:radiation effects; D005609:Free Radicals; D005720:Gamma Rays; D008647:Mesocricetus; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D013696:Temperature
D005609:Free Radicals; D011837:Radiation-Protective Agents; D001205:Ascorbic Acid; D004121:Dimethyl Sulfoxide