Mitochondrial membrane potential measurement

TMRE (Cat. 87917, Sigma) was used to measure levels of ΔΨm. TMRE is a cationic dye that is rapidly and reversibly accumulated by healthy mitochondria. A decrease in the levels of TMRE indicates a reduction in mitochondrial membrane potential levels. Experimentally, a fraction of cells (5 × 10⁵) from the peritoneal lavage was labeled with freshly prepared TMRE at 37°C in the dark for 30 min. Unstained controls were treated similarly but dyes were omitted. Dye-loaded cells were immediately re-suspended in cold DPBS containing 1% fetal bovine serum and analyzed immediately by flow cytometry at the R-phycoerythrin channel. Ten thousand cells were routinely collected, and data were expressed as the mean fluorescence intensity in arbitrary units from the average of at least three separate experiments.