Background: Radiation induced brain and cerebellum injury is common in patients receiving radiotherapy for head and neck tumors. Administration of antioxidants before radiation as vitamin E, nigella sativa oil and melatonin could be valuable in limiting this injury.
Material and Methods: 40 rats were divided into five different groups. Group Ι: served as the control group and subdivided into 4subgroups. subroup Ia: negative control, subgroup Ib: animals received vitamin E only (300 mg/kg orally once, subgroup Ic: animals received nigella sativa oil only (1ml/kg orally once and subgroup Id: animals received melatonin only 100 mg/kg intraperitoneally once: Group ΙΙ: animals were exposed to x ray irradiation (XRI) (8 Gy whole body). Group ΙΙΙ: animals were pretreated with vitamin E (300 mg/kg orally once 1h before XRI. Group ΙV: animals were pretreated with nigella sativa oil(1ml/kg orally once1h before XRI). Group V: animals were pretreated with melatonin (100 mg/kg intraperitoneally once 1h before XRI). Animals were sacrificed 48h after irradiation. Brain and cerebellum were dissected, formalin fixed and processed for histological and glial fibrillary acidic protein (GFAP) immunostainig. The number of GFAP positive astrocytes were counted and statistically analyzed using SPSS program.
Results: Radiation induced loss of lamellar pattern in the cerebral cortex with degeneration and necrosis of cortical nerve cells. In the cerebellum, purkinje cell degeneration was observed. Radiation induced a significant increase in the number of GFAP positive astrocytes in both cerebral and cererbellar cortices compared to the control group. In groups treated with vitamin E, nigella sativa oil and melatonin, there was partial improvement in cerebral and cerebellar changes with a significant decrease in the number of GFAP positive astrocytes.
Conclusion: The use of antioxidants such as vitamin E, nigella and melatonin could limit radiation induced injury in brain and cerebellum.