Figure 6: HIF-1α knockdown induced apoptotic cell death under preconditioning with Mn complexes in neuronal cells.

(a) PC12 cells were transfected with plasmid DNA which knocked down HIF-1α protein expression and the results was tested by western blot. (b) Statistical analysis of the percentage of HIF-1α protein expression. (c) Cell apoptosis detected by a flow cytometer. After 6 h transfection, the cells were pre-incubated with (a) neuronal medium (control), (b) neuronal medium, (c) 1 (10 μM) for 12 h (d) 1 (10 μM) for 24 h, (e) 2 (1 μM) for 12 h and (f) 2 (1 μM) for 24 h and then treated with H₂O₂ (200 μM) for 12 h (c–f) Statistical analysis of the apoptotic cell percentage. The data are presented as mean ± SD of three independent experiments (Student’s T. Test, *P < 0.05, **P < 0.01 vs. only H₂O₂ stimulation but without any pretreatment).