Abstract: Abstract: Objective To explore the dynamic changes of endothelial barrier antigen (EBA) and vascular endothelial growth factor (VEGF) expressions in cerebral cortex under the condition of blood-brain barrier damage in rats following radiation-induced brain injury, which provided clinical references. Methods Forty-eight clean grade male SD rats were divided into the control group and 7 d, 14 d, 28 d after brain irradiation group (n=12 for each group) by using stochastic indicator method. The radiation-induced brain injury model was established by using electronic computer X-ray tomography technique. The 3% Evans blue (EB) was injected into rats according to the dose of 3 mL/kg via the tail vein, then the blood vessels of cerebral cortex were exposed after having a craniotomy. EB extravasation was detected by microcirculation microscope. The permeability of blood-brain barrier was evaluated by using microscope vascular camera device. The expressions of EBA and VEGF in the cerebral cortex were measured by immunohistochemistry staining in each group. Results Both of EB extravasation and VEGF expression in rat cerebral cortex were significantly increased in injury group at day 7, 14 and 28 after brain irradiation compared with those of control group (P＜0.05), and which were gradually decreased from day 7 to day 28 after brain irradiation. There were significant differences in EB extravasation and VEGF expression between the injury subgroups (P＜0.05). There was a positive correlation between EB extravasation and VEGF expression (r=0.898, P < 0.001).The expression levels of EBA were decreased at different time points in injury groups compared with those of control group(P＜0.05), and gradually increased from day 7 to 28 after injury. There were significant differences in expression levels ofEBA between injury subgroups (P＜0.05). The expression of EBA was negatively correlated with EB extravasation (r=-0.866,P < 0.001). Conclusion The increases of blood-brain barrier permeability have important relation to the decreases of EBA expression and the increases of VEGF expression after radiation-induced brain injury.

Key words: radiation injuries, experimental, brain injuries, blood-brain barrier, vascular endothelial growth factors, rats, Sprague-Dawley, radiation-induced brain injury, endothelial barrier antigen rats, Sprague-Dawley, radiation-induced brain injury, endothelial barrier antigenendothelial growth factor, rats