Fig. 6.

Sodium sulfide alters mitochondrial function and inhibits complex III activity. Oxygen consumption rate (OCR) was measured in cells treated with 476 μM Na₂S or degassed water for 4 h using a Seahorse Bioscience XF24 Extracellular Flux Analyzer (A). Basal respiration is the OCR prior to addition of oligomycin (B). The spare capacity was calculated as the FCCP OCR minus the basal OCR (C). Complex I activity was measured as the rotenone-sensitive oxidation of NADH at 340 nm in cell lysate (D). Complex III activity was measured as the antimycin A-sensitive oxidation of cytochrome c at 550 nm in cell lysate (E). All data are from 3 independent experiments. Error bars represent SD and * represents P < 0.05 using a Student's t-test. Refer to the web version for easier identification of cell lines in Figure 6A.