Development of white matter gliosis in ex vivo slice culture model. (A-D) Compared to 0 DIV (A), there was a marked increase in GFAP+ astrocytes in the white matter at 1 DIV (B), 5 DIV (C), and 9 DIV (D), and cells exhibited a reactive phenotype (D, inset). (E-H) Compared to 0 DIV (E), there was a marked increase in Iba1+ microglia/macrophages in the white matter at 1 DIV (F), 5 DIV (G), and 9 DIV (H), and cells exhibited a reactive phenotype (H, inset). (I-L) bHABP staining at 0 DIV (I) was low in the white matter in contrast to the elevated staining in the peri-neuronal nets of the cerebral cortex. Compared to 0 DIV (I), there was a progressive increase in bHABP in the white matter at 1 DIV (J), 5 DIV (K), and 9 DIV (L). (M-O) In contrast to the cortex, areas of white matter gliosis (M) were enriched in bHABP staining (N); double labeling is shown in O. (P) HA (red) exhibited a perinuclear pattern in areas of gliosis (GFAP, green). Scale: A-H, 100 μm; I-O, 200 μm; P, 25 μm; Insets D, E, H, 10 μm. Ctx, cortex; SVZ, subventricular zone; WM, white matter.