Long-Term Effects of Iron Particle (HZE) Irradiation on Mouse Spermatogonia

Abstract

High-energy (HZE) cosmic ray particles in space present an environmental hazard, especially to long-duration high altitude space travel. The energy released when these particles slow down and stop in living tissue causes deleterious biological effects, including death of cells. In order to study and quantitate the effects of this radiation, a number of cell systems could be used. The spermatogonial cell population in mouse testes has a rapidly dividing cell population, can be examined three days after irradiation, and is one of the most sensitive tissues to radiation. Therefore, it is ideally suited for quantitative studies of radiation effects. Previous work has shown that the various types of spermatogonial cells differ in their radiation sensitivity and that this can be very easily evaluated with the light/electron microscope. Using the system of staging established by Oak-berg and Huckins, the mixed or single cell population can be evaluated. Our work, using this method, has revealed cell sensitivity at doses as low as one rad. In these experiments, the animals were sacrificed three days post-irradiation because this is the time when maximum cell loss can be viewed. However, we are now reporting long term results of HZE particles using iron irradiation.