Fig. 6

Apocynin reduces blood–brain barrier disruption and neutrophil infiltration in the white matter of EAE spinal cord. a Images represent immunohistochemical characterization of IgG extravasation in the thoracic spinal cord of EAE mice. Sham-operated spinal cord section showed only weak IgG immunoreactivity (IR) primarily confined to the BBB-deficient area. Some perivascular extravasation of IgG (brown color) was detected in the thoracic spinal cord of normal mice. Prominent extravasation of IgG is seen throughout the parenchyma of the spinal cord 21 days after MOG injections (EAE + vehicle, n = 3). However, the extensive diffusion of IgG IR was reduced by apocynin treatment in EAE mice (EAE + apocynin, n = 3). Scale bar represents 200 μm. b The graph represents percent area of IgG IR in the white matter of thoracic spinal cord with or without apocynin treatment in sham-operated and EAE mice. Data are mean ± sem (n = 3). *p < 0.05 compared with apocynin-treated group. c Fluorescence images display neutrophil infiltration by myeloperoxidase (MPO) staining in the spinal cord. EAE mice (EAE + vehicle, n = 5) revealed intensive infiltration of neutrophil in the white matter of the spinal cord. However, apocynin treatment reduced neutrophil infiltration into the white matter of spinal cord in EAE mice (EAE + apocynin, n = 5). Scale bar represents 100 μm. d The bar graph shows the quantification of MPO(+) cells in the spinal cord. The number of MPO(+) cells is significantly different between vehicle (Veh)- and apocynin (Apo)-treated group in the EAE mice. Data are mean ± sem (n = 5). *p < 0.05 compared with apocynin-treated group