Figure 2: Evaluation of sulfatide-induced PMNL apoptosis. (a), (c), and (d) PS exposure of PMNL was determined using Annexin V-Alexa Fluor 647. PMNLs (1.5 × 106/mL) were cultured for 2.5 h at 37°C without or with sulfatides (indicated concentration). Then, flow cytometry determined the percentage of Annexin V positive cells. Shown are the mean ± SD (a) and flow cytometric histogram samples of baseline (c) and 25 μg/mL sulfatide (d) groups, from six independent experiments. (b) PMNLs (1.5 × 106 cells/mL) were added or not added with 25 μg/mL sulfatides, and, after 1.5 h at 37°C, the BIOMOL Carboxyfluorescein Multicaspase Activity Kit used flow cytometry to count the cells with activated caspases. Shown is the mean ± SD of three independent experiments.