Figure 1.

Seahorse assay and outline of the prolonged reactive oxygen species (ROS) exposure experiment. (A) Mitochondrial respiration is inferred by measuring oxygen consumption rate (OCR). OCR is measured three times over 18 min at each measurement phase. Initially, basal respiration is measured. The complex V inhibitor oligomycin is then used to determine how much of basal respiration is ATP-linked respiration and proton leak respiration. Then, a protonophore, carbonyl cyanide-p-trifluoromethoxyphenyl-hydrazon (FCCP) is used to drive the respiratory chain to its maximal rate by collapsing the inner membrane gradient, allowing maximal respiratory capacity to be determined. To determine non-mitochondrial respiration, antimycin A and rotenone, Complex III and I inhibitors, are added to stop the respiratory chain. Reserve capacity is calculated as the difference between basal respiration and maximal respiratory capacity. (B) Prolonged exposure (96 h) to a low concentration of DMNQ is used to simulate chronic exposure to a low level of ROS while other cells had no exposure to DMNQ as a control.