Figure 7
The topographical distribution of reactive astrocytes within the superior frontal gyrus and hippocampus in an Alzheimer's disease case. (A) Histological reconstruction of frontal gyrus gray matter made by the superimposition of identical areas of adjacent sections displaying reactive astrocytes with heterogenous morphologies in the different layers. 6F/3D β-amyloid (Aβ) plaques are in red color, reactive astrocytes positive for glial fibrillary acidic protein (GFAP+) are brown. Representative areas (B-D) are in the right column. (B) A uniform distribution of GFAP+ astrocytes (arrows) with small somata and densely stained neuropil in the superficial layers. (C) In the deeper layers, densely stained GFAP+ astrocytes and neuropil are concentrated around Aβ-neuritic plaques (arrows). (D) In the cortical lamina-VI bordering the white matter, GFAP+ astrocytes (arrows) were distributed more evenly as very few Aβ-neuritic plaques were observed in this region. (E) Histological reconstruction of the hippocampal CA1 and the dentate gyrus showing differences in the localization and intensity of immunoreactivity of GFAP+ astrocytes. GFAP+ astrocytes are brown, the α7nAChRs are gray. Representative areas are displayed in the corresponding inserts (F-I). (F) In the CA1 alveus and stratum oriens, intensely stained small somata of GFAP+/α7nAChRs astrocytes and networks were observed. (G) Throughout the stratum pyramidale, large somata of GFAP+ astrocytes without α7nAChRs (arrows) were found dispersed throughout GFAP+ network. (H) Differences in the intensity of immunoreactivity and the number of GFAP+ astrocytes were detected in the stratum lacunosum-moleculare (upper layer, strong staining) and the molecular layer of the dentate gyrus (bottom layer, weak staining). (I) In the granular layer, weakly stained GFAP+ astrocytes and network (top layer) were accompanied by very strong stained α7nAChR/GFAP+ astrocytes (bottom layer, gray). Videocapture was performed with ×10 (A, E) and ×20 (B-D, F-I) objective lenses magnification.