Figure 4.

Different crystal induced neutrophil cell death involves neutrophil necroptosis. Human neutrophils were exposed to crystals of calcium oxalate (0.2 mg/ml), MSU (0.2 mg/ml), calcium phosphate (0.2 mg/ml), and silica (0.2 mg/ml) for 2 hours after 30 minutes pretreatment with 100 µM Nec1s or 5 µM NSA. Crystal-induced cell death was visualized by live cell imaging using propidium iodide stain (PI, red area). Acridine orange (AO) stained live cells (magnification 20x) (A) and mean fluorescence intensity was quantified (B). All representative images are from a single experiment. Data were obtained from three independent experiments each performed in duplicate. Data represent means ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001 versus medium. After 30 minutes pretreatment with NSA (5 µM), neutrophils exposed to crytsals were fixed and visualized using scanning electron microscope (scale bar = 10 µm) (C).