Irradiation par microfaisceau de particules alpha : Implication des espèces réactives de l'oxygène dans l'effet de voisinage.

Maïté Hanot 1, 2
1 LEEL - UMR 3685 - Laboratoire d'Etudes des Eléments Légers
NIMBE UMR 3685 - Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M)
Abstract : Ionizing radiation-induced bystander effects arise in bystander cells that receive signals from directly irradiated cells. To date, free radicals are believed to play an active role in the bystander response, but this is incompletely characterized. To mark temporal and spatial impacts of bystander effect, we employed a precise -particle microbeam to target a small fraction of sub-confluent osteoblastic cell cultures (MC3T3-E1). We identified the cellular membrane and mitochondira like two distinct places generating reactive oxygen species. The global oxidative stress observed after irradiation was significantly attenuated after filipin treatment, evidencing the pivotal role of membrane in MC3T3-E1 cells bystander response. To determine impact of bystander effect at a cell level, cellular consequences of this membrane-dependant bystander effect were then investigated. A variable fraction of the cell population (10 to 100%) was individually targeted. In this case, mitotic death and micronuclei yield both increased in bystander cells as well as in targeted cells demonstrating a role of bystander signals between irradiated cells in an autocrine or paracrine manner. Our results indicate a complex interaction of direct irradiation and bystander signals that lead to a membrane-dependant amplification of cell responses.
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Maïté Hanot. Irradiation par microfaisceau de particules alpha : Implication des espèces réactives de l'oxygène dans l'effet de voisinage.. Biophysique [physics.bio-ph]. Université Paris Sud - Paris XI, 2008. Français. ⟨tel-00429902⟩

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