Astrocytic C3 upregulation in APP transgenic mice. A, C, Representative double immunostaining for C3 and astrocytic marker GFAP in the hippocampus of APP/TTA transgenic mice at 8 months of age (A) and APP/PS1 transgenic (Tg) animals at 18 months (C). Littermate TTA and WT mice were used as controls for bigenic APP/TTA and Tg mice, respectively. B, D, Quantification of C3 fluorescence intensity in GFAP+ cells in APP/TTA (B) or Tg (D) hippocampal regions. N = 126 (TTA), 145 (APP/TTA), 87 (WT), 88 (Tg) cells collected randomly from sections of three animals per genotype. E, Representative double immunostaining for C3 and microglial marker Iba1 in the hippocampus of Tg animals. F, qPCR measurement of C3 mRNA levels in WT primary astroglial and microglial cultures treated with 100 nm Aβ42 or reverse peptide (rAβ42). Three internal controls (GAPDH, PGK1, and ACTB) were used. N = 3 cultures per condition. Scale bars: 50 μm. *p ≤ 0.05; ***p ≤ 0.001 (B, D, Student's t test; F, two-way ANOVA followed by Bonferroni's post hoc analysis).