Dominant expression of angiogenin in NeuN positive cells in the focal ischemic rat brain

Angiogenin (ANG) is a potent angiogenic factor. The purposes of this study were to observe the change of the expression level of ANG and to identify the cell types that express ANG in the focal ischemic rat brain. The rat brain ischemia-reperfusion model was produced by a 2 h occlusion of the left middle cerebral artery with a nylon thread followed by reperfusion for 1 day, 3 days, 7 days or 14 days. The expression levels of ANG in the rat brain at each time points were determined by western blotting. The co-staining of ANG with NeuN was observed using double immunofluorescent labeling combined with confocal laser scanning microscope. We found that the expression level of ANG increased significantly in the rat brain 1 day, 3 days, and 7 days after ischemia (P < 0.05), and peaked 3 days after ischemia. Double immunofluorescent labeling showed that ANG positive cells were mostly co-stained with NeuN. Our observations suggest that the level of ANG increased significantly in the rat brain after ischemia. The upregulated ANG was mostly expressed by neurons.