FIGURE 6.

Cell viability, Cu²⁺-Aβ is more cytotoxic than Aβ. a, Aβ(1–42) as preformed fibrils, 3 μm, with and without the presence of 1.5 μm Cu²⁺ was added to PC12 cells to give a concentration in the well of 2.7 μm Aβ and 1.35 μm Cu²⁺. Cell concentration was 5.9 × 10⁴ cells/ml. 2.5 μm Cu²⁺ was added to the cells alone to test Cu²⁺ toxicity. Blank is buffer only. All preparations were incubated with the cells for 24 h, and then 10% (v/v) alamarBlue was added. The data shown here are after total incubation for 70 h. b, 10 μm monomeric Aβ(1–40) with a range of Cu²⁺ concentrations was incubated with PC12 cells for 6 days. AlamarBlue was then added and the reading taken. Cell concentration was 5.4 × 10⁴ cells/ml. All cell experiments were conducted in Opti-MEM, pH 7.4. Error bars are S.E., n = 3. ***, p = 0.001; **, p = 0.02.