Abstract
Many researcher studying in area of radiation biology have been believed that active short life-time radicals such as OH and H radicals, play an important role to express genotoxic effects of radiations in cells,such as mutation and cancer induction. However, in 1993 we found a new type ofradicals with long life-time(T1/2 is over 20hr) in gamma ray irradiated golden hamster embryo (GHE) cells at room temperature by using ESR spectroscopy. When vitamin C is added to the gamma- or X-irradiated cells at 20 min or 6 hr after the irradiation, respectively, vitamin C scavenge LLRsimultaneously with the drastic suppression of genotoxicity such as mutation and transformation.Addition of vitamin C to the cells before or after irradiation does not have any effects onreducing cell death and chromosomal aberration. Since reactive oxygen species (ROS) disappearwithin microsecond after the irradiation,vitamin C does not scavenge the ROS but LLR.Therefore,we have proposed that LLR must be responsible radicals for inducing mutation, and probablyimportant for the genotoxicity in the irradiated mammalian cells. [J Radiat Res 44:379 (2003)]
