Figure 4. Age-dependent retention of fusion protein in brain.

(a) Ex vivo brain retention expressed as % ID per g brain tissue in tg-ArcSwe (n=17) and WT (n=15) mice of different ages 72 h post injection. (b) Aβ protofibril levels in brain tissue obtained from tg-ArcSwe mice of different ages. (c) Pearson's correlation analysis of brain concentrations of fusion protein 72 h post injection and concentration of Aβ protofibrils in brain tissue of tg-ArcSwe mice. Each diamond represents one animal. (d) Total Aβ40 and Aβ42 levels in brain tissue from tg-ArcSwe mice of different ages. (e) Nuclear track emulsion and CD31 staining. The fusion protein was not accumulated in capillaries (red arrows) but to a large extent reached the brain parenchyma (black arrows). (f) Nuclear track emulsion and Congo staining revealed that the fusion protein was also located around insoluble amyloid deposits. Scale bar, 50 μm. Each symbol represents one animal, the line and error bars (a–d) indicate group mean±s.d. ***P<0.001 and NS is nonsignificant by two-way analysis of variance followed by Bonferroni's post hoc test (a). Representative images from triplicate experiments are shown in e and f.