Fig. 2: Gentamicin exposure increases mitochondrial ROS and the ATP:ADP ratio in HK-2 cells within 30 min and GGA ameliorates gentamicin-induced mitochondrial ROS and preserves the ATP:ADP ratio.

a Fluorescent images of the ATP:ADP ratio measured by a probe sensitive to both ATP and ADP show that gentamicin exposure triggers a larger proportion of ATP (red) relative to ADP (green) in renal cells. b Serial ATP:ADP ratio measurements show that gentamicin causes a gradual increase in ATP:ADP ratio, whereas GGA preserves the baseline ATP:ADP ratio in gentamicin-exposed cells. Data are normalized to control. c Cells exposed to gentamicin show an increase in mitochondrial H₂O₂ measured by the mitochondrial HyPer probe as a decrease in the excitation peak at 420 nm proportional to the increase in the peak at 500 nm. d GGA treatment prior to gentamicin exposure ameliorated this increase in mitochondrial H₂O₂. e Ratiometric images of 500 nm:420 nm excitation in cells with MitoHyPer probe show a similar increase in mitochondrial ROS (denoted in red) in vehicle control cells relative to GGA-treated cells. f Vehicle-treated cells exhibited a marked increase in mitochondrial H₂O₂ during gentamicin exposure and GGA treatment completely prevented mitochondrial H₂O₂ accumulation during gentamicin exposure. n = 4, Error bars = SEM. Bars = 5 µm.