Heme causes macrophage cell death with early loss of plasma membrane integrity and morphologic features of necrosis. Peritoneal macrophages (2 × 105/well) from C57Bl/6 mice were left untreated or stimulated with heme in the absence of serum. Macrophage cell death was dependent on heme concentrations (μM) at 6 hours after stimulation (A), and occurs as early as 3 hours after treatment with heme at 30μM (B). After the indicated time of stimulation with heme, the supernatants were collected for LDH determination. Data are representative of 5 independent experiments performed in triplicates and represent mean ± SEM (*P < .01; **P < .001 compared with control group). (C) Representative transmission electron micrographs of control and heme-treated macrophages (30μM) after 6 hours of stimulation. Scale bars = 2 μm.
