Mrs Catherine Belzung, Prof. of University of Tours, member
Mr Jean-Jacques Hauw, Prof. of University of Paris VI, member
Mr François Coudoré, Prof. of University of Paris XI, member
Mr Maâmar Souidi, IRSN, referee
Mr Dominique Laurier, IRSN, referee
It remains today a deficit of knowledge about the existence of biological and health effects, other than cancer risk, after exposure to ionizing radiation. The aim of my research is to better understand the nature and importance of these biological effects at level of the central nervous system.
The main results show that external exposure or internal exposure (uranium) to ionizing radiation leads to impaired locomotor activity, decreased memory, increased anxiety or changes in sleep-wake cycle. In order to explain these effects, two mechanistic strategies have been considered and based on the modulation of neurotransmitters and the oxidative stress. Disturbances of the cholinergic system and NO-ergic and have been demonstrated after external or internal exposure. We also demonstrated the importance of oxidative stress in the mechanism of action of ionizing radiation in the brain. This work also showed that these effects are dependent on brain structure (cortex> hippocampus), the animal model (post-natal> adult), time of exposure (subchronic> chronic) and dose.
These results therefore demonstrate the radiosensitivity of the central nervous system, even for low doses. In the future we will continue our efforts in understanding the mechanisms of neuro-toxicity of ionizing radiation, including studies of the role of neurogenesis, through the network of excellence DoReMi.