Figure 2

Measurement of mitochondrial membrane depolarization following sodium nitroprusside (SNP) treatment of human osteoarthritic (OA) synoviocytes. A) Cells were incubated for 12 hours in medium alone (control), with 0.5 mM SNP, or with 1 μM valinomycin (positive control). The mitochondrial membrane potential was determined by flow cytometry using DePsipher. Data acquisition was performed using a FACScan flow cytometer as detailed in the Methods section. A representative density plot for each treatment group is shown. The numbers represent the percentage of the mean ± standard error of each population from eight different experiments performed in duplicate (*p < 0.01). B) Histograms represent DePsipher fluorescence of SNP-stimulated synoviocytes. Relative to the control, green fluorescence (light line) increases while red fluorescence (dark line) decreases in SNP- or valinomycin-stimulated synoviocytes. The numbers represent the mean ± standard error of red/green fluorescence ratio values of eight different experiments performed in duplicate (*p < 0.01).