Fig. 2

Quantitatively evaluation of immune-positivity of toxic Aβs in brain sections. After administering phosphate-buffered saline (PBS) in A anti-amyloid β oligomer (AβO) 6H4 antibody fragments (Fabs) (6H4 Fab PM) and B anti-Aβ 3D6 Fabs encapsulated in PMs (3D6 Fab PM), C anti-AβO 6H4 Fabs (6H4 Fab), and D Alzheimer’s disease (AD) model and E untreated wild-type (WT) mice, immunohistochemistry with anti-Aβ 82E1 antibody was performed. Panels A–E reveal significantly narrower plaque diameters F and smaller 82E1positive areas G in the 6H4 Fab PM group (black bars) than in the PBS group (white bars). Images of immunofluorescent positive signals for anti-AβO 6H4 antibody (magenta) and thioflavin S (green) in AD mice treated with PBS (H), 6H4 Fab PMs (I), 3D6 Fab PM (J), and 6H4 Fab (K), and WT mice (L). Quantitative analysis of the % region of interest (ROI) for 6H4 antibody (M) and thioflavin S (N) positive signals of AD mice observed in panels H–L revealed significantly reduced %ROI and thioflavin S-positive signals in the 6H4 Fab PM group compared with that in the PBS group. Immunoreactive-images for anti-N3pE Aβ antibody in AD mice treated with PBS (O), 6H4 Fab PM (P), 3D6 Fab PM (Q), and 6H4 Fab (R) and WT mice (S). Enlarged views are presented inside dashed lines on each figure. N3pE Aβ-positive Aβ plaques in the 6H4 Fab PM group showed small diffuse-like plaques without Aβ cores (P). Quantitative values of the immunostained N3pE Aβs represent the average numbers of plaques in 10 figures in panels O–S. The 6H4 Fab PM group showed significantly smaller N3pE Aβ antibody-positive areas (T) and diameters (U) than those in the PBS group. Scale bar = 100 μm. One-way analysis of variance with Tukey’s post-hoc test was performed. Values = mean ± standard error of the mean. *p < 0.05, **p < 0.01