RBE and genetic susceptibility of mouse and rat spermatogonial stem cells to protons, heavy charged particles and 1.5MeV neutrons

• Published in: Advances in space research 2007-01, Vol.39 (6), p.1093-1101
• Main Authors: Vaglenov, A., Fedorenko, B., Kaltenboeck, B.
• Format: Article
• Language: English
• ISSN: 0273-1177
• DOI: 10.1016/j.asr.2007.01.066

The main purpose of the present study is to provide data on RBE and genetic susceptibility in the mouse and the rat when exposed to protons, HZE particles and neutrons. Genetic damage from exposure to 50MeV and 9GeV protons, 4GeV/nucleon helium ions, 4GeV/nucleon carbon ions and 1.5MeV neutrons was studied in adult (CBAxC57Bl/6J) F1 mice. Damage from 9GeV protons and 4GeV helium ions was studied in adult Wistar rats. The incidence of reciprocal translocations (RT) induced in the spermatogonial stem cells of each species was recorded. RBE values were derived by comparing linear regression coefficients from dose-responses within the same dose-range for each of the radiation types tested and super(6) super(0)Co gamma -rays or by means of a direct nonparametric method. RT yields measured after mouse and rat spermatogonial irradiation with protons, heavy charged particles and neutrons fit the linear model of the dose-response relationship. Relative to super(6) super(0)Co gamma -rays, RBE values are as follows for mouse spermatogonia: 0.9 for 50MeV protons; 1.3 for 9GeV protons; 0.7 for 4GeV helium ions; and 1.3 for 4GeV carbon ions. For rat spermatogonia, values were: 1.7 for 9GeV protons and 1.3 for helium ions. Compared to mice irradiated using the same experimental design, rats were more susceptible to high-LET radiations, with susceptibility assessed by genetic damage to their spermatogonial stem cells. The RBE of 1.5MeV neutron is about 6.6.