Figure 5

Representative photomicrographs of GFAP (A-F), Iba-1 (G-L), and LFB (M-R) immunohistochemistry of the external capsule, internal capsule, and the fornix of P22/23 control (A, C, & E for GFAP; G, I, and K for Iba-1; M, O, & Q for LFB) and hydrocephalic animals (B, D, & F for GFAP; H, J, & L for Iba-1; N, P, & R for LFB). GFAP staining in the hydrocephalic animals reveals severe reactive astrocytosis when compared to the saline control animals. Panel A shows typical characteristics of resting astrocytes that includes lightly stained cell bodies with thin processes. Panel B demonstrates distinctive characteristics of reactive astrocytes including a darkly stained cell body with thick processes (arrow). For Iba-1, control animals (G, I, & K) exhibit resting microglial cells which are characterized by a small unremarkable cell body with thin processes. The hydrocephalic animals (H, J, & L) display reactive microglia cells which are typified by a darkly stained, enlarged, distorted cell body with thick processes (arrows, J and L). At the end stages of reactivity they exhibit a "balled up" appearance known to represent a phagocytic state (arrow, L). LFB staining is dark and uniform in the saline controls which indicates the preservation of myelin (M, O, & Q). Whereas, the hydrocephalic animals exhibit a more diffuse and variable staining pattern, providing evidence of demyelination most likely resulting from the mechanical stress that accompanies HCP (N, P, & R). Scale bar = 25 μm for all panels except O and P, scale bar = 50 μm.