Aβ-stimulated MAC-1 expression is inhibited by PPARγ agonists. Primary mouse microglia were plated onto uncoated culture wells (A, C) or surface-bound fibrillar Aβ1–40 (48 pmol/mm2; B, D) for 48 hr in the presence of vehicle (DMSO; A, B) or 10 μm troglitazone (trog.; C, D). Cells were fixed and stained for MAC-1. Immunoreactivity was visualized using 3,3′-diaminobenzidine tetrahydrochloride as the chromogen.