Expressions and cell identification of gp91phox in peri-contusional area after traumatic brain injury (TBI). (A) In sham-operated animals, weak immunoreactivity for gp91phox was observed in the cortex (upper panel). Two days after TBI, gp91phox immunoreactivity was dramatically increased in the peri-contusional area (lower panel). Scale bars = 400 μm. (B) Co-immunostaining of gp91phox with cell markers in the peri-contusional region. Immunostaining was carried out using antibodies for gp91phox (shown in green) together with Integrin alpha M (CD11b) (upper), glial fibrillary acidic protein (GFAP) (middle), and neuronal nuclear antigen (NeuN) (lower). Microglia, astrocyte, and neuron markers are shown in red. Gp91phox immunoreactive cells were co-labeled with all cell markers. Particularly strong expression of gp91phox was detected in microglial-like cells (CD11b-positive cells). Cells were counter-stained with DAPI to show nuclei (blue). Scale bars = 20 μm.