Selective mitochondrial superoxide generation in vivo is cardioprotective through hormesis

Free Radic Biol Med. 2019 Apr:134:678-687. doi: 10.1016/j.freeradbiomed.2019.01.034. Epub 2019 Feb 4.


Reactive oxygen species (ROS) have an equivocal role in myocardial ischaemia reperfusion injury. Within the cardiomyocyte, mitochondria are both a major source and target of ROS. We evaluate the effects of a selective, dose-dependent increase in mitochondrial ROS levels on cardiac physiology using the mitochondria-targeted redox cycler MitoParaquat (MitoPQ). Low levels of ROS decrease the susceptibility of neonatal rat ventricular myocytes (NRVMs) to anoxia/reoxygenation injury and also cause profound protection in an in vivo mouse model of ischaemia/reperfusion. However higher doses of MitoPQ resulted in a progressive alteration of intracellular [Ca2+] homeostasis and mitochondrial function in vitro, leading to dysfunction and death at high doses. Our data show that a primary increase in mitochondrial ROS can alter cellular function, and support a hormetic model in which low levels of ROS are cardioprotective while higher levels of ROS are cardiotoxic.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Apoptosis
  • Disease Models, Animal*
  • Herbicides / pharmacology
  • Hormesis*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mitochondria, Heart / drug effects
  • Mitochondria, Heart / metabolism*
  • Mitochondria, Heart / pathology
  • Myocardial Reperfusion Injury / metabolism
  • Myocardial Reperfusion Injury / pathology
  • Myocardial Reperfusion Injury / prevention & control*
  • Myocytes, Cardiac / cytology*
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / metabolism
  • Paraquat / pharmacology*
  • Rats
  • Rats, Wistar
  • Superoxides / metabolism*


  • Herbicides
  • Superoxides
  • Paraquat