Plasma Membrane Integrity Assay

Neutrophils (1 × 10⁶/mL) were re-suspended in 100 µL PBS and 50 µL of 20 µg/mL propidium iodide (PI) solution (in PBS) was then added. The membrane integrity was determined by using a BD-Accuri flow cytometer (Becton Dickinson). Neutrophils (1 x 10⁶ cells) were resuspended in 100 µL of PBS, and 50 µL of propidium iodide (PI) solution (20 µg/mL in PBS) were then added. Propidium iodide is a highly water-soluble fluorescent compound that cannot pass through intact membranes and is generally excluded from viable cells. It binds to DNA by intercalating between the bases with little or no sequence preference. Fluorescence was measured using the FL2 channel (orange-red fluorescence = 585/42 nm). Ten thousand events were analyzed per experiment. Results are expressed as the percentage of cells that present intact membranes. The same procedure was described in our previous study (47).