RAS Activation was Associated with Mitochondrial Injury. Electron microscopy shows damage to the inner membrane and cisterna of mitochondria and vacuous areas within mitochondria areas with RAS activation that are prevented by MitoTEMPO treatment. RAS activation did not significantly change the percent area occupied by mitochondria compared with the control (38 ± 2%, 34 ± 5%, 36 ± 4% of cytoplasmic surface area, for control, ACE8/8, MitoTEMPO groups, respectively; P=0.16 comparing control vs. ACE8/8, and P=0.45 comparing ACE8/8 vs. MitoTEMPO), a finding consistent with the MitoTracker Green analysis.