Effects of oligomeric versus fibrillar Aβ(1-42) on phagocytic function of microglial cells. (A) Dose dependence of phagocytosis stimulated by oAβ(1-42) and fAβ(1-42). BV-2 cells were incubated with the indicated Aβ(1-42) (0.2~10 μM) for 30 min before being exposed to microspheres for an additional 30 min; (B) The number of microspheres taken up per BV-2 cell with or without oAβ(1-42) or fAβ(1-42) treatment; (C) Time course of phagocytosis stimulated by oAβ (1-42) or fAβ(1-42) in microglial cell. BV-2 cells were preincubated with oAβ(1-42) (1.0 μM) or fAβ(1-42) (5.0 μM) for 30 min, 3 h, 6 h,12 h before the addition of microspheres for 30 min. (D) Phagocytosis stimulated by oAβ(1-42) or fAβ(1-42) in primary microglia. Cells were incubated with the oAβ(1-42) (1.0 μM) or fAβ(1-42) (5.0 μM) for 30 min before the addition of microspheres. Each value is expressed as mean ± S.E. of three independent experiments. ***P < 0.001, compared with the oAβ-treated groups. #P < 0.05, compared with the 30 min treated groups.