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

• Published in: Radiation research 1993-12, Vol.136 (3), p.361-365
• Main Authors: Yoshimura, Toru, Matsuno, Kiyotaka, Miyazaki, Tetsuo, Suzuki, Keiji, Watanabe, Masami
• Format: Article
• Language: English
• Subjects: Albumins; Animals; Ascorbic Acid - pharmacology; Biological and medical sciences; Biological effects of radiation; Cell Line; Cricetinae; Dimethyl Sulfoxide - pharmacology; Dose-Response Relationship, Radiation; Dosimetry; Electron paramagnetic resonance; Electron Spin Resonance Spectroscopy; Embryo, Mammalian - chemistry; Embryo, Mammalian - drug effects; Embryo, Mammalian - radiation effects; Embryonic cells; Embryos; Free Radicals; Fundamental and applied biological sciences. Psychology; Gamma Rays; Irradiation; Mesocricetus; Radiation dosage; Radiation-Protective Agents - pharmacology; Radioprotection; Room temperature; Temperature; Tissues, organs and organisms biophysics; Vitamin C
• ISSN: 0033-7587; 1938-5404
• DOI: 10.2307/3578548

Formation of free radicals in golden hamster embryo (GHE) cells produced by γ irradiation at 77 and 295 K has been studied by electron spin resonance (ESR) spectroscopy. The yields of free radicals in the γ-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 γ 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 γ irradiation is suppressed upon the addition of vitamin C to the GHE cells. When an aqueous solution of albumin ($0.1\ {\rm kg}\ {\rm dm}^{-3}$) is γ-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.