Increased CD147 and MMP-9 expression in the normal rat brain after gamma irradiation

Radiation-induced vascular injury is a major complication of Gamma knife surgery (GKS). Previous studies have shown that CD147 and MMP-9 are closely associated with vascular remodeling and pathological angiogenesis. Thus, we analysed changes in CD147 and MMP-9 expression in the cerebral cortex to investigate the correlation between CD147 and MMP-9 in the rat following GKS. Adult male Wistar rats were subjected to GKS at a maximum dose of 75 Gy and then euthanized 1 to 12 weeks later. Using immunohistochemistry and western blot analysis, we found that CD147 and MMP-9 expression were markedly upregulated in the target area 8–12 weeks after GKS when compared with the control group. Immunofluorescent double staining demonstrated that CD147 signals colocalized with CD31, GFAP and MMP-9-positive cells. Importantly, CD147 levels correlated with increased MMP-9 expression in irradiated brain tissue. For the first time, these data demonstrate a potential relationship between CD147 and MMP-9 following GKS. In addition, our study also suggests that CD147 and MMP-9 may play a role in vascular injury after GKS.