EARLY EFFECT OF MEDIUM-DOSE IONIC IRRADIATION (20Gy)ONTHE EXPRESSION OF c-fos IN THE RAT BRAIN / 解剖学报

ABSTRACT

Objective To investigate the early effect of medium-dose ionic irradiation on the expression of Fos protein in the rat brain. Methods Fos protein was observed in rat brains at times ranging from 24 hours to 4 weeks after hemispheric irradiation (single-fraction maximal dose of 20Gy) with the immunohistochemical technique. Results Compared with that of the un-radiated rats,the expression of Fos protein in the irradiated brain decreased distinctly 24 hours and 1 week after irradiation.However,the quantity of Fos immunopositive cells increased gradually afterwards.At four weeks after radiation,expression of Fos protein recovered progressively in medulla oblongata and pons,in which Fos immunopositive cells were more than those in control group.In contrast,expression level of Fos protein in mesencephalon,diencephalons or telencephalon was still less compared with that of the un-irradiated rats.Conclusion The result suggested that the neuronal activity might be inhibited in certain nuclei of the rat brain in early stages after hemisphere irradiation,and this inhibitory phenomenon was more obviously in higher neural centers.