Abstract Details

Title Effects of Ionizing Radiation on Human Microglial Cells

Topic Neuro-oncology

Presentation(s) P02 - (-)

Poster/Presentation
Number 165

Objective

Background BACKGROUND: Cranial radiotherapy can cause damage to normal human brain, which may involve neurogenesis defects. Delayed effects may complicate the acute immediate effects and in particular have been associated with neurodegeneration and cognitive decline. These delayed effects may arise from the slow death of irradiated cells, damage to cells that survive the radiation exposure, or from negative effects on normal cell replenishment non-targeted brain cells from neural stem cells. Recent study showed that microglial may contribute to the recovery of neural stem cell after ionizing radiation. .

Design/Methods DESIGN/METHODS: In this study, we investigated the direct effects of low and high doses ?-rays on cell survival, proliferation, and oxidative stress of human microglial cell line CHME.

Results RESULTS: After 4h and 24 h of ionizing irradiation, apoptosis was evaluated by flow cytometry analysis of FITC Annexin V and propidium iodide staining. There was no significant increased apoptosis and most cells were survived. Apoptotic cell populations showed similar distribution from 0 to 8 Gy of ?-rays. MTT assay showed that cell proliferation was decreased as irradiation dose goes up, which is dose-dependent. The decrease was significantly after 48 hour of high dose ionizing irradiation (p<0.05), especially after 72 hours of 8 Gy irradiation (p<0.01). We also examined reactive oxygen species (ROS) formation in human microglial cells exposed to ionizing irradiation. After 24 hour post irradiation, microglial cells showed significant oxidative stress. Cells exposure to 2 or 4 Gy exhibited peak levels of ROS (p<0.01 and p<0.05, respectively).

Conclusions CONCLUSIONS: These data suggest that microglial cells may be resistant to ionizing irradiation but its proliferation is inhibited by ionizing irradiation. In addition, ROS may play a role in the response of microglial after irradiation.

Authors/Disclosures
PRESENTER	No disclosure on file
Nizar Souayah, MD, FAAN (NJMS)	Dr. Souayah has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Takeda. Dr. Souayah has received publishing royalties from a publication relating to health care.
Vittorio Martinelli (S. Raffaele Hospital)	Dr. Martinelli has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Novartis, Biogen, Sanofi Genzyme, TEVA and Merck. Dr. Martinelli has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Merck .

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