Microglial activation.

A. Effects of oAβ_25–35 (10 µg/rat) icv injection on microglial reaction using Iba-1 immunolabeling in the amygdala, frontal and parietal cortex, hypothalamus (paraventricular nucleus: PVN) and hippocampus (CA1 & CA3 regions) determined in control untreated rats and 6 weeks after Aβ_25–35 scrambled peptide (10 µg/rat; negative control) or Aβ_25–35 injection. Activated microglia was visualized with Alexafluor 488-labeled specific antibody against Iba-1 (green immunolabeling), while the nucleus was counterstained with DAPI (blue labeling). 3v: third ventricle. Scale bar  = 100 µm. B–E. Variations in Iba1 levels in the frontal cortex (B), amygdala (C), hippocampus (D) and hypothalamus (E), determined in rats by western blot 6 weeks after icv injection of scrambled Aβ_25–35 peptide (10 µg/rat; negative control) or oAβ_25–35 (10 µg/rat). Iba1 (17 kDa) variations were normalized with β-tubulin (β-tub, 55 kDa) variations and compared with untreated rats (control group: C). The results are expressed as means ± SEM. *p<0.05 and **p<0.01 vs. control group, +p<0.05 and ++p<0.01 vs. scrambled treated rats. The number of animals in each group is indicated within the columns.