Skip to main content
. 2019 Sep 12;11(9):527. doi: 10.3390/toxins11090527

Figure 1.

Figure 1

Cobra cardiotoxin (CTX)3 induced apoptotic death of U937 cells. (A) Effect of CTX3 on the viability of U937 cells. Cells were incubated with indicated CTX3 concentrations for 4 h. (Inset) U937 cells were treated with 150 nM CTX3 for indicated time periods. Cell viability was determined using methlythiazolyldiphenyl-tetrazolium bromide (MTT) assay. Results are expressed as the percentage of cell survival relative to the control. Each value is the mean ± SD of three independent experiments with triplicate measurements; (B) Flow cytometry analyses of annexin V-PI double staining CTX3-treated cells. U937 cells were incubated with 150 nM CTX3 for 4 h. On the flow cytometric scatter graphs, the left lower quadrant represents remaining live cells. The right lower quadrant represents the population of early apoptotic cells. The right upper quadrant represents the accumulation of late apoptotic cells; (C) Western blot analyses of procaspase-3 and poly(ADP-ribose) polymerase (PARP) degradation in CTX3-treated cells. U937 cells were incubated with 150 nM CTX3 for 4 h; (D) Viability of CTX3-treated cells was restored by pretreatment with caspase inhibitors. U937 cells were pretreated with 10 μM Z-VAD-FMK (pan-caspase inhibitor) or Z-DEVD-FMK (caspase-3 inhibitor) for 1 h, and then incubated with 150 nM CTX3 for 4 h. Each value is the mean ± SD of three independent experiments with triplicate measurements (* p < 0.05).