This study aims to investigate the impact of gamma-radiation on the cerebral- and cerebellar-cortex of rat's brain. Animals were whole-body exposed to 3 Gy, every 3 days, up to 9 Gy, and sacrificed 1 h, 1, 3, 7 & 10 days post the last radiation-dose. Irradiation triggers oxidative stress. Superoxide dismutase, catalase, glutathione reductase decreased, malondialdehyde and protein carbonyl increased from the 1st hour till the 10th day in both tissues. Glutathione peroxidase and glutathione decreased from the 1st hour in the cerebral-cortex, and 3rd day in the cerebellar-cortex. Irradiation increased the inflammatory marker, tumor necrosis factor-alpha, and the apoptotic markers, cytochrome-c and caspase-3 from the 1st hour till the 10th day in both tissues. β-amyloid was observed the 7th and 10th day in cerebral-cortex and 3rd, 7th and 10th day in cerebellar-cortex. Irradiation change the level of neurotransmitters. Norepinephrine decreased from the 1st hour in both tissues, while dopamine, epinephrine, aspartic acid, glutamic acid decreased, and gamma amino butyric acid increased from the 1st hour in the cerebral-cortex and later on the 3rd day in the cerebellar-cortex. Electroencephalographic measurement (EEG) showed significant decreases in the frequencies of beta-(>12 Hz) alpha-(7-12 Hz), theta-(4-7 Hz), and delta-rhythms (1-4 Hz) from the 1st hour in both occipital and parietal areas of the brain. Gamma-irradiation triggers oxidative stress, change the level of neurotransmitters, increase inflammatory and apoptotic responses, enhance deposition of amyloid plaque in the cerebral- and cerebellar- cortex, and decrease brain electrical activity in occipital and parietal areas of the brain.
Keywords: Apoptosis; Beta amyloid; Cerebellar-cortex; Cerebral-cortex; EEG. γ-radiation; Neurotransmitters.
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