Figure 2.

Gfa2–VIVIT reduces astrocyte activation in Tg mice. A, Representative Western blots and mean ± SEM protein levels for the astrocyte marker GFAP from hippocampal homogenates of WT and Tg mice treated with vehicle and Gfa2–EGFP (Ct) or Gfa2–VIVIT (VIV). In the bar graph, GFAP levels are normalized to GAPDH internal controls and expressed as a percentage of the WT Ct group (⁺p < 0.001 Tg Ct vs WT Ct and WT VIV; ^#p < 0.01 Tg VIV vs WT VIV; *p < 0.05 Tg VIV vs WT Ct). B–E, Low-magnification (B1–E1) and high-magnification (B2–E2) representative images of astrocytes immunohistochemically labeled in hippocampal CA1 for the presence of GFAP. CA1 s.p., CA1 pyramidal cell layer. Scale bar, 500 μm. F, Representative region showing GFAP immunoreactivity before (raw) and after conversion to a binary image (cells in blue) for quantification of possible changes in astrocyte size. G, Histograms of binary images showing the size of individual astrocytes (total pixel area per cell) counted per unit area (mean ± SEM) in CA1 of Tg Ct and Tg VIVIT mice. The last column in each histogram indicates the number of cells counted with a total pixel area in excess of 1000. H, Weibull distributions for histograms shown in G. Curve parameters were compared using Z tests (see Results). I, Representative binary images of astrocytes sorted into small-, medium-, and large-sized categories based on total pixel area. J, Total number of astrocytes (mean ± SEM per square millimeter) counted in CA1 for Tg Ct and Tg VIVIT mice. K, Mean ± SEM astrocyte size (pixel area) for astrocytes counted in G. L–N, The proportion of small, medium, and large astrocytes (mean ± SEM, expressed as percentage of total cells) in area CA1 for Tg Ct and Tg VIV groups. For all panels, ⁺p < 0.001, ^#p < 0.01, *p < 0.05.