Effect of caspase-3 inhibitor on cytotoxicity (A) and induction of apoptosis (B) by13-MTD. Cells pre-cultured for 24 h were incubated with PBS (no inhibitor), caspase-3 inhibitor (20 μ M Z-DEVD-FMK) and negative control inhibitor (20 μ M Z-FA-FMK) for 60 min and then further incubated with 0.25 mM of fatty acids samples for 4 h. On completion of the incubation, cell viability was determined by MTS assay (A), and induction of apoptosis was assayed as described in legend to Fig. 2 (B). Data are mean ± SE of triplicates analyses. Data not sharing the same letter within the treatment shows the statistically significant difference at p < 0.05 by Tukey-Kramer test.