Effect of delayed hypoxic incubation and reoxygenation on the kinetics of neutrophil apoptosis.
(A) Neutrophils were incubated at 5 × 106 cells/mL in 21% oxygen for the time periods indicated at right before they were transferred to an incubator containing 3% oxygen. Top and bottom curves represent the time courses for the onset of apoptosis in neutrophils cultured throughout in 21% or 3% oxygen, respectively. Percentage apoptosis was assessed morphologically from cytocentrifuge preparations. (B) Effect of reoxygenation was examined by incubating neutrophils in 3% oxygen for increasing periods of time (indicated at right) before they were transferred to an incubator containing 21% oxygen. Top and bottom curves represent the kinetics for the onset of apoptosis for neutrophils incubated throughout in 21% oxygen or 3% oxygen, respectively. In panels A and B, data represent the mean ± SEM of 4 separate experiments, each performed in triplicate.
