Detection of active caspases using FLICA assay. Histogram showing the levels of active caspases in each of the treatment groups from the two cell types (CHME-5 and SH-SY5Y) at the end of week 4. The levels are expressed in fluorescence units/106 cells. P (*P > 0.05) value indicates that there was no significant difference in the level of active caspases between the rotenone treated and untreated CHME-5 cells. Rotenone treated SH-SY5Y cells showed significantly increased (**P < 0.001) levels of active caspases (fluorescence units) compared to untreated control cells. Each column represents the mean and standard deviation from three independent experiments.