(C) CD68 coverage in the old APPPS1 tissue (14 DIV) incubated with conditioned media collected from young WT slices (young CM) or with non-conditioned slice culture media (Ctr). CD68 coverage is increased upon incubation of the APPPS1 tissue with the young CM. The values are normalized to CD68 coverage of the Ctr and represent mean ± SEM from 3 independent experiments, each experiment including 2 independent slice culture dishes (**P < 0.01). 