Inability of heat and cold shock, glucose deprivation, and mitochondrial inhibitors to modulate the rate of neutrophil apoptosis in vitro.
(A) Neutrophils (5 × 106/mL) were incubated at 42°C (heat shock) or 4°C (cold shock) for 1 hour before culture at 37°C under normoxic (21% oxygen) conditions for 5 or 20 hours. Control cells were preincubated for 1 hour at 37°C before culture under normoxic (open bar) or hypoxic (3% oxygen; diagonally striped bar) conditions. Cells were recovered at the time points indicated, and apoptosis was assessed morphologically. Data represent mean ± SEM of 7 independent experiments, each performed in triplicate (*P < .05 compared with time-matched controls). (B) Neutrophils were cultured under normoxic (21% oxygen; open bars) or hypoxic (3% oxygen; filled bars) conditions in IMDM containing either 4.5 g/L glucose (control), 10 g/L glucose, no glucose, or sodium pyruvate. In all conditions IMDM was supplemented with 10% dialyzed (glucose-free) fetal calf serum. Cells were recovered at 20 hours, and apoptosis was assessed morphologically. Data represent the mean ± SEM of 4 independent experiments, each performed in triplicate. (C) Neutrophils were cultured under normoxic (21% oxygen) (open bars) or hypoxic (3% oxygen) (filled bars) conditions for 20 hours in the presence or absence of sodium azide (1 mM), potassium cyanide (1 mM), or rotenone (100 ng/mL), as indicated. Apoptosis was assessed morphologically. Data represent the mean ± SEM of triplicate incubations from 1 of 2 representative experiments.
