The purpose of this study was to establish the impact of oxidative stress in the damaged brain tissue, irradiated with two different dose levels, a single dose of 8 and 15 Gy. In addition, the histological findings caused by ionizing radiation in the early period was investigated. The levels of MDA, GSH, SOD, CAT, GSH-Px and selenium were estimated in brain tissue. For the histological examination, brain tissues were examined at photo light microscope. MDA contents of brain after 8 Gy and 15 Gy γ-irradiation were markedly elevated compared with group 1. Brain SOD activity decreased after exposure to 15 Gy γ-irradiation, there was a significant difference compared with group 1 and group 2. Brain GSH-Px activity in group 2 and group 3 was enhanced when compared with group 1. CAT activity of brain after 15 Gy γ-irradiation was markedly decreased compared with group 1 and group 2. GSH levels were significantly lower in group 2 and 3 when compared with group 1. In this study, brain selenium levels were not found to be markedly changed after irradiation. In group 3 basal membrane structure was found to be highly thicker when compared group 1 and group 2. As a result, in the early period, high doses of ionizing radiation (8 Gy and 15 Gy) influences the oxidant-antioxidant system in guinea-pig brain, after the formation of LPO, antioxidant levels alter and this may play a role in reducing tissue damage caused by RT whereas the histologic changes occur when the dose is increased. |