Figure 4. Retinal blood vessels stained for Aβ.

A. Inner retinal vessels stained for Aβ (red), Iba-1 (green) and neuronal cell bodies (blue) at 24 months. The amyloid deposits can be seen to be at focal points along the vessel rather than being continuous. B. Choroidal vessels also accumulated Aβ, however, the accumulation of this material appeared to be specific to a sub-group of vessels with other showing no sign of Aβ accumulation. This is taken from a 12 months old animal. C. Immunostaining of retinal section of a 12 months old animal using the colorimetric method (3,3-diaminobenzidine) to confirm the presence of Aβ in the outer segment of the photoreceptor and in the blood vessels. D. Negative control of the colorimetric staining showing the absence of staining.