Spotheim-Maurizot M, Savoye C, Sabattier R, Charlier M
Centre de Biophysique Moléculaire, CNRS, Orléans, France.
Bull Cancer Radiother. 1996;83 Suppl:27s-31s. doi: 10.1016/0924-4212(96)84880-8.
The effect of fast neutrons on cells is different from that of gamma-rays: the relative (to gamma) biological effect (RBE) is higher than one and the oxygen enhancement ratio (OER) is lower than that of gamma-rays. We searched for differences between the effects of the two radiations on DNA, the critical target of radiations. Using a model plasmid DNA we observed that for the same absorbed dose, fast neutrons induce twice fewer single strand breaks (SSB) and 1.5 more double strand breaks (DSB) than gamma-rays. A transition metal ion, the Cu++, is a better sensitizer of DNA breakage with fast neutrons than with gamma-rays. In anoxia, cysteamine, a positively charged thiol, is a better radioprotector against neutrons than against gamma-rays. In presence of cysteamine, the OER is lower for neutrons than for gamma-rays. These results are discussed in terms of different physical properties of the two types of radiation.
