Fig. 3. HNP-1 rescues mammalian cells from amyloid-induced cell toxicity. Dose-dependent protection effect of HNP-1 against amyloid Aβ-, hCT-, and hIAPP-induced (a) cell toxicity determined by MTT assay and (b) cell membrane disruption determined by LDH assay. Cells were incubated with amyloid peptides (25 μM) for 24 h in the absence or presence of 1–25 μM HNP-1. Untreated cells were set as controls for 100% MTT reduction and 0% LDH activity, cells after lysis were set for 100% LDH activity, and cells only incubated with HNP-1 (grey bars) were also analyzed for comparison. All data represent mean ± s. d. of three independent experiments. Statistical analysis (n = 3) was conducted for cells treated with HNP-1 or amyloid peptides alone relative to the control (^○p < 0.05; ^○○p < 0.01; ^○○○p < 0.001), as well as cells treated with both HNP-1 and amyloid peptides relative to cells treated with amyloid peptides alone (*p < 0.05; **p < 0.01; ***p < 0.001). (c) Representative fluorescence microscopy images of cells treated with freshly prepared amyloid peptides (25 μM) in the absence or presence of 5 μM HNP-1. Untreated cells were set as a control. Red and green fluorescence indicate dead and live cells, respectively. Scale bars = 100 μm.