Effects Of Iodine-131Intracranial Brachytherapy On Cognitive Function And Hippocampal Formation Of Rats

Objective:To study the effects of iodine-131intracranial brachytherapy on cognitive function and hippocampal formation of ratsMethods:The geometry of radiotherapy capsule was detected by CT scan after implanted onto rat brain surface by surgical procedure. Thirty-two SD rats were randomly divided into two groups exposed respectively to131I of0mCi and5mCi, The head CT scan was performed before and8days,32days after exposure. The neurobehavioral changes were observed by Morris water maze at1week and4weeks respectively after radiation. The rats were sacrificed and hippocampus was taken out. Ultra-structural changes of the prepared samples were observed using HE staining and transmission electron microscope.Results:1.There were no significant differences for the two groups in terms of the swim latency, the time of swim in the platform quadrant and the times of swim through the plateau region at1week and4weeks after radiation.2.The HE staining of the hippocampus shows no significant difference between the two groups. Distinct dilation of endoplasmic reticulum, occurrence of numerous secondary lysosomes were found in the brachytherapy group.Conclusion:Iodine-131intracranial brachytherapy is safe for the rats as far as cognitive functions are concerned. There is no significant changes in the HE staining, and there are ultra-structural changes in the TEM study.