Changes of myelin in the rat brain after whole-brain irradiation

The whole brain of SD rats was irradiated by the single dose of 2,10,or 30Gy.The enzyme-linked immunosorbent assay was used for the content measurement of myelin basic protein(MBP)in telencephalon tissue at 1 week,1 month,3 months and 6 months after irradiation.Both the Luxol fast blue staining with image analysis and the electron microscope were used to investigate the histomorphologic and ultrastructural characteristics of demyeli- nation.The MBP content of telencephalon tissue in control rats were 78-82μg/mL,there were no difference in all the 2Gy irradiated,1 week and 1 month after 10 to 30Gy irradiated groups.But at 3 and 6 months after 10Gy and 30Gy irradiated rats,there MBP content were in 50-62μg/mL level,which were a significant decrease compared with the control groups(p0.01).Typical demyelination in corpus callosum of rats was observed in 30Gy irradiation after 6 months,but no evidence of demyelination was seen in all the other rats.The ultra-structural changes of myelin and oligodendrocytes were detected in 10Gy and 30Gy exposure after 1 to 6 months observed by electron microscope.All the demyelination changes were seen correlated with the dosage and duration after irradiation.These findings indicate that the radiation-related molecular and pathological characteristic changes of demyelination can be assessed in 3 to 6 months after single 10Gy to 30Gy whole-brain irradiation in SD rats.