Alda-1 attenuates rotenone-induced activation of mitochondrial apoptotic pathway. (A, C) Compared to rotenone-treated cells, Alda-1 administration greatly attenuated rotenone-induced increase in protein level of cytosolic Bax, cytochrome c, active caspase-9 and active caspase-3 in SH-SY5Y cells and cultured SN neurons. (B, D) Quantification of level of apoptosis related proteins measured by the use of a densitometer showed that Alda-1 treatment inhibited rotenone-induced increase in cytosolic Bax, cytochrome c, active caspase-9 and active caspase-3 in SH-SY5Y cells and cultured SN neurons in a concentration-dependent manner. Each bar represents the mean ± SD value of at least three independent experiments.