Effect of 4-
-methylhonokiol on Aβ accumulation in the cortex and hippocampus. (A) Immunoreactive protein of anti-Aβ1-42 antibody was investigated in the cortex and hippocampus. 6 μm-thick sections of brains from mice were incubated with 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-injected mouse. Amyloid plaque detection via congo red staining (B) and thioflavin S (C) was performed in the cortex and hippocampus. 6 μm-thick sections of brains were incubated with 0.2% congo red solution or thioflavin S solution for 20 min and counterstained with hematoxylin. Arrow indicates amyloid plaque which is clearly higher in the cerebral cortex and hippocampus of LPS-injected mouse. The histograms depict the mean congophilic plaque load ± SEM in mice brain. (D) The levels of Aβ1-42 and Aβ1-40 were assessed by using a specific Aβ ELISA as described in Methods. (E) The activity of β- and γ-secretase was investigated by using each assay kit as described in Methods. Values measured from each group of mice were calibrated by amount of protein and expressed as mean ± S.E. (n = 5). The values in the western blot band indicate average density over β-actin from three animals. #, Significantly different from control group (p < 0.05). *, Significantly different from LPS-treated group (p < 0.05). Control, saline-treated group. LPS, lipopolysaccharide. MH, 4-O-methylhonokiol.