Fig. 4

The SSd-induced apoptotic effects on HSC-T6 and LX-2 cells were partially caspase-3-dependent. (a) HSC-T6 and LX-2 cells were treated with SSd (1 μM) for 0, 8, 12 and 24 h, and the total cellular protein content was subsequently extracted to detect the pro-caspase-3, pro-caspase-9, caspase-3 and caspase-9 expression. The expression level of active caspase-3 and caspase-9 increased. (b and c) The protein expression level of caspase-3 and caspase-9 was also detected by ELISA kits. (d and e) HSC-T6 cells were treated with SSd (1 μM) for 24 h, and subsequently fixed by 70 % alcohol. The cells were stained with PI, and the cell cycle distribution was detected by flow cytometry. LX-2 cells were also treated with SSd (1 μM) for 24 h, and cell cycle distribution was detected by flow cytometry. The SSd-induced sub-G1 phase of HSC-T6 and LX-2 was partially inhibited by the caspase-3 inhibitor Z-DEVD-FMK. (f) SSd-induced cytotoxicity was detected by the MTT assay, and was also partially impeded by Z-DEVD-FMK. *P < 0.01