Abstract
Irradiation is a common treatment in tumor therapy. Radiation can cause DNA damage and death of proliferating cells. During clinical radiation therapy, the radiation dose could range from 1.8 to 20 Gy depending on targets. In the normal cases, 2 Gy-radiation treatment will cause cancer cell death. In the brain tissue, hippocampal neuron is not as sensitive to radiation. Some studies indicated the low dose radiation would induce cellular protective mechanism to promote cell survival and DNA repair. In our study, we demonstrate the low dose radiation would promote survival of hippocampal neurons based on MTT assays. 0.2 Gy radiation treatment had no effect on the cell number. We hypothesized to investigate the relationship between irradiation and mitochondrial function. However, radiation treatment did not affect membrane potential, ROS level and mitochondrial DNA copy number. Interestingly, the low dose radiation (0.2 Gy) may promote the mitochondria fusion found by immunofluorescence staining. The relative level of Drp1, a fission protein, was decreased after radiation treatment. Hippocampus is the region of the brain that suffers damage in Alzheimer's disease. To determine whether low dosage radiation would have beneficial effect on neurodegenerative disease, we treated hippocampal neuron with beta-amyloid (Aβ) to mimic Alzheimer's pathology followed by radiation therapy. Our results so far did not show protective effect of radiation on Aβ-treated hippocampal neurons.