Figure 7. Absence of microglia results in reactive astrocytes.

(A) Specimen confocal images illustrating astrocytes in 6–10-week-old mice by GFAP immunoreactivity (green) in the CA1 stratum radiatum. Scale bars, 50 µm and 10 µm (for expanded view). (B–D) Analyses of GFAP⁺ cell density (B), percentage of area covered by GFAP⁺ astrocytes (C) and mean GFAP intensity (D). (E) Specimen confocal images illustrating astrocyte morphology by GFAP immunoreactivity (left) and their 3D reconstruction (right). Scale bar, 10 µm. (F–H) Sholl analysis-derived values of the number of intersections with Sholl radii at increasing distance from the soma (F) and the resulting total number of intersections (G) and total process length (H) of astrocytes. (I) Specimen confocal images illustrating astrocytes by GFAP (green) and MEGF10 (red) immunoreactivity in the CA1 stratum radiatum of mice aged P22-23. Scale bar, 50 µm. (J–M) Analyses of the percentage of area covered by GFAP⁺ astrocytes (J), mean GFAP intensity (K), area covered by MEGF10⁺ astrocytes (L) and mean MEGF10 intensity (M). (N) Left: Specimen confocal images showing Homer1 signal (green) within GFAP⁺ astrocytes (red). Middle and right: Close-up images of astrocytes with orthogonal projections at the level of the crosshairs showing Homer1 (middle) or VGluT1 (right) signal within GFAP⁺ astrocytes. Scale bars, 20 µm and 2 µm (for orthogonal projections). (O, P) Quantification of volume (%) of Homer1 (O) and VGluT1 (P) signal co-localizing with GFAP volume. Data information: Age of mice was 6–10 weeks (A–H) and P22–P23 (I–P) Data are represented as mean ± SEM. Numbers on bars indicate number of slices and (number of animals). P values are from unpaired Student’s t tests. Source data are available online for this figure.