Figure 4

Cytosolic expression of High-mobility group box 1 (HMGB1) in Glial fibrillary acidic protein (GFAP)-positive cells of cortex from animals with subarachnoid hemorrhage (SAH). (A, B) HMGB1 immunostaining images obtained from cortex of a sham (A), and a day-1 (B) animal respectively. (C, D) Merged images of HMGB1 immunostaining (red) and 4',6-diamidino-2-phenylindole (DAPI) nuclear staining (blue). (E, F) Merged images of HMGB1 immunostaining (red) and GFAP immunostaining (green). Enlarged images (a, b, c, d, e, f) on the right side of each panel also highlight the increased number of cytosolic HMGB1-positive cells in cortex from SAH animals while few cytosolic HMGB1-positive cells were also positive for GFAP. Arrows indicated the cytosolic HMGB1. The results indicated that astrocytes were not the main source of released HMGB1, at least at this early time point. Scale bars represent 20 μm.