(C) Old APPPS1 tissue was incubated with conditioned media collected from cultured WT primary microglial cells (old alone + MG CM, grey bar) or with unconditioned slice culture media as a control (old alone + Ctr, white bar). Quantitative analysis of core-only plaques at 14 DIV reveals enhanced amyloid plaque clearance upon incubation of the old APPPS1 tissue with conditioned media collected from cultured primary microglia. The values are expressed as percentages of core-only plaques from the total number of amyloid plaques and represent mean ± SEM from 3 independent experiments, each experiment including 2 independent slice culture dishes (*P < 0.05). 