Effect of cryopreservation on the response of different biological systems to γ-ray exposure: A feasibility study

Cryopreservation of cells, tissues or organisms (i.e. the storage at liquid-nitrogen or nitrogen vapour temperature) offers the most secure form of preservation, allowing cells to be maintained unaltered for a long time and preventing them from ageing. On the other hand, the multi-year exposure of cryo-preserved cells (like: stem and germ cells) to the environmental γ-ray background might induce a radiation-damage accumulation, due to the inhibition of cellular repair mechanisms, and contribute to cancer or non-cancer pathology risk assessment when such cells should be transplanted in individuals. To investigate the effect of the cryo-preservation on the cell response to radiation exposures, the response of different biological systems (bacteria and mammalian cells) to γ-rays has been evaluated after irradiation in cryo-preserved and culture conditions, as a function of dose and doserate, in terms of a variety of cellular and molecular end-points.