Effect of LPS on Aβ accumulation in the cortex and hippocampus. The levels of Aβ1–42 and Aβ1–40 (A) were assessed by using a specific Aβ ELISA as described in the Materials and methods section. Values measured from each group of mice were calibrated by amount of protein and expressed as mean ± S.E. (n = 5) *Significant different from control (p < 0.05). Immunostaining of Aβ1–42 in the cortex and hippocampus (B). Mice were injected intraperitoneally with either 250 μg/kg LPS or sterile saline (0.9% NaCl) daily for 3 or 7 days before sacrifice. Forty μm-thick sections of brains from mice were incubated with rabbit polyclonal anti-Aβ1–42 antibody and counterstained with hematoxylin. Arrow indicates Aβ1–42 accumulation which is clearly higher in the cerebral cortex and hippocampus of LPS-treated mouse and was the highest in the mouse treated with daily injection for 7 days. Figure in box shows the intracellular accumulation of Aβ1–42 (detected anti-Aβ1–42 immunofluroscene staining after DAPI staining the cells) in the pyramidal neurons of the hippocampus at the high magnification. Arrow bar indicates accumulation of Aβ1–42.