NMO pathology in seropositive rats at 5 days after intracerebral needle injury. A. (top) NMO-IgG administration and intracerebral needle injury protocol. (bottom) Rats received 1 mg NMO-IgG or control IgG by intraperitoneal injection. Cytotoxicity in rat serum obtained at 8 and 24 h was measured by Alamar blue assay in AQP4-expressing CHO cells at 1 h after incubation with different concentration of heat-inactivated rat serum and 5% human complement (S.E., n = 3). For comparison data shown for heat-inactivated pooled human sera from NMO seropositive patients to which 5% human complement was added. B. (left) AQP4 and human IgG staining in brain of rats receiving NMO-IgG at 1 day after intracerebral needle injury. Needle track shown as yellow line. (right) Higher magnification of boxed region along with data for control IgG. C. (left) AQP4, GFAP and MBP immunofluorescence at 5 days. Needle track shown as yellow line and lesion demarcated by white dashed line. (middle) Higher magnification. (right) Summary the areas of loss of AQP4, GFAP and MBP immunostaining. Each point is from a different rat.