Cardiac complex II activity is enhanced by fat and mediates greater mitochondrial oxygen consumption following hypoxic re-oxygenation

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Shi Chao Zhu
  • Chen Chen
  • Yu Na Wu
  • Majid Ahmed
  • Sung Joon Kim
  • Yong Feng Shao
  • Yin Hua Zhang


Recent evidence suggests that mitochondrial complex II is an essential mediator of myocardial ischemia–reperfusion injury. The present study aimed to investigate the effects of fatty acid supplementation or high-fat diet (HFD) on cardiac mitochondrial activity. The changes of complex I and complex II activities and mitochondrial oxygen consumption rate (OCR) following hypoxia and re-oxygenation under these conditions were studied. Our results have shown that OCR (mitochondrial activity) was significantly increased with palmitoylcarnitine supplementation in mitochondria-enriched fraction from C57BL/6 mice hearts. Mitochondrial complex I activity was unaffected by palmitoylcarnitine but complex II activity was enhanced. Re-oxygenation following 30-min hypoxia transiently increased OCR but such an effect on OCR was abolished by complex II inhibitor, malonate, but not by complex I inhibitor, rotenone, despite that complex I activity was significantly increased with re-oxygenation following hypoxia in the presence of palmitoylcarnitine. Furthermore, OCR and complex II activity were significantly increased in the mitochondria from high-fat diet mice heart compared with those of normal or low-fat diet mice. Re-oxygenation to mitochondria following 30-min hypoxia increased OCR in all three groups but significantly more in HFD. Malonate abolished re-oxygenation-induced OCR increment in all groups. Our results indicate that complex II activity and OCR are enhanced with palmitoylcarnitine or in HFD mice heart. Although re-oxygenation following hypoxia enhanced complex II and complex I activities, complex II plays an important role in increasing mitochondrial activity, which may be instrumental in myocardial injury following ischemic reperfusion.

Bibliographical metadata

Original languageEnglish
Pages (from-to)367-374
Number of pages8
JournalPflugers Archiv European Journal of Physiology
Issue number3
Early online date20 Feb 2020
Publication statusPublished - 1 Mar 2020