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.