Fig 4.

Caspase-3 activity in neuroblastoma cells in the presence or absence of EGb761. (A) Caspase-3 enzymatic activity assay in the N2a cells (wt), and the swe/Δ9 (swe/Δ9) cells alone, or treated with EGb761 for 48 h. Data are expressed as percentage of the maximum caspase-3 activity in swe/Δ9 cells, which, in average, was equivalent to 1.6 pmol/mg of protein/min. *, statistical significance (P < 0.05, n = 4) by unpaired t test. (B) Representative Western blots of caspase-3 activation in the control and the mutant cells. Lane 1: unstimulated N2a cells; lane 2: N2a cells stimulated with 1 μM butyric acid for 12 h; lane 3: mutant cells stimulated with butyric acid for 12 h; lane 4: mutant cells treated with 100 μg/ml of EGb761 for 48 h before stimulation with butyric acid; lane 5: N2a wt cells treated with 0.1 μM Aβ for 12 h; lane 6: N2a cells treated with 100 μg/ml of EGb761 for 48 h before treatment with 0.1 μM Aβ for 12 h. Arrows indicate cleaved (activated) caspase 3 at about 17 kD. The lower blot is an immunoblot of actin indicating that same amount of proteins were loaded in each lane. Results are representative of two independent experiments.