Fig 1: Gamma frequency light flicker reduces amyloid load in APP/PS1 mice. (a) Immunohistochemistry with anti-Aß (6E10, green) in cortex, CA1, CA3, and DG regions of 6-month-old male APP/PS1 mice following dark, 40 Hz, 80 Hz light flicker for 1 h/day for 7 days, scale bar represents 100 µm, n = 7 mice/group. DAPI labeling of cell nuclei (blue). (b) Soluble and insoluble Aß1-40 and Aß1-42 levels in cortex of 6-month-old male APP/PS1 mice after 7 days of 1 h per day dark, 40 Hz, or 80 Hz flicker were performed by ELISA (n = 8 mice per group). Data are presented as mean ± SEM. *p < 0.05 vs. APP/PS1 group, **p < 0.01 vs. APP/PS1 group, n.s = not significant, by two-way ANOVA with Tukey's post hoc multiple comparisons test. (c) Representative Western blot showing levels of APP, sAPPa, sAPPß, and Aß in cerebral cortex of 6-month-old male APP/PS1 mice with dark, 40 Hz, or 80 Hz light flicker (n = 4 mice per group). Data are presented as mean ± SEM. *p < 0.05 vs. APP/PS1 group, **p < 0.01 vs. APP/PS1 group, #p < 0.05 vs. indicated group, ##p < 0.01 vs. indicated group, by two-way ANOVA with Tukey's post hoc multiple comparisons test. (d) Relative immunoreactivity of sAPPß normalized to GAPDH. (e) Relative immunoreactivity of sAPPa normalized to GAPDH. (f) Relative immunoreactivity of Aß normalized to GAPDH. (g) The expression levels of synaptophysin, PSD-95, AMPAR (GluR1), GAT-1, GABAAR a1, GABAAR ß2, GABABR1, and GABABR2 were detected by flow cytometry in different groups (n = 4 mice per group). MFI: mean fluorescence intensity. Data are presented as mean ± SEM. *p < 0.05 vs. APP/PS1 group, **p < 0.01 vs. APP/PS1 group, n.s = not significant, by two-way ANOVA with Tukey's post hoc multiple comparisons test