The expression of endothelial barrier antigen (EBA) and S100B in the rat parietal cortex following brain irradiation

• We conduct a model of rat brain radiation-induced injuries by CT.
• We evaluated the dynamic expression of EBA and S100B after CT irradiation.
• EBA and S100B play an important role in the early radiation-induced brain injury.

Objective: To visualize the dynamic expression of endothelial barrier antigen (EBA) and S100B in the rat parietal cortex at the acute phase of radiation-induced brain injury using computed tomography (CT). Methods: A rat model of brain injury was established by CT scanning. The expression of EBA and S100B in the parietal cortex was analyzed at different time points by immunohistochemistry (IHC) and western blotting. Results: Significantly increased EBA expression was detected in the animals in the control group compared with the animals receiving CT radiation, which exhibited significantly reduced EBA levels within the vessel walls (F=33.29, p<0.05), particularly at day 3 after radiation. Both immunohistochemical staining and western blot analysis indicated that the positive expression levels of S100B among radiation groups were increased compared with the control group (IHC, F=28.05, p<0.05; WB, F=175.3, p<0.05). The expression of S100B peaked at day 3 (IHC, 102718±8710; WB, 2320±0.129), and subsequently decreased. Conclusion: CT radiation can induce altered EBA and S100B protein expression. Decreased EBA expression levels indicated that the integrity of the blood–brain barrier (BBB) was affected by radiation. The destruction of the BBB and the expression of S100B might play important roles in the incidence and repair of the early radiation-induced brain injury, and radiation represents a cause of mental disorders.