Astrocytic iNOS expression and plaque associated nitrotyrosine. (A) Costaining of Aβ1–42 and GFAP at 16 months detected activated astrocytes nearby Aβ plaques. Astrocytic iNOS and confocal staining of iNOS (red) and Aβ1–42 (green) or nitrotyrosine (red) and Aβ1–42 (green). (B) RT-PCR for GFAP and iNOS in APP [V717I] mice at 3 (3 m) and 16 months (16 m) of age. (C) Quantification of iNOS-positive astrocytes in the hippocampus (HC, black bar) and frontal cortex (FC, hatched bars) of APP transgenic mice (tg) and wild type controls (wt) at 3 and 16 months. (D) Densitometry of GFAP, iNOS and GAPDH mRNA from APPV [7171I] mice at 3 (black bars) and 16 months (hatched bars). (E) Confocal staining of CD11b positive microglia and GFAP labelled astrocytes showed that both cells were located in close neighbouring in APP [V717I] mice at 3 month of age. (n = 6, ANOVA followed by a TUKEY test, n.s. = non significant, ***p < 0.001). Bar graph = 50 μm.