Docosahexaenoic Acid Induced Apoptosis In H9c2 Cells And Changed Cardiac Function After Ischemia-Reperfusion Injury

• Author / Creator

  Qadhi, Rawabi

• Cardiovascular disease (CVD) remains one of the leading causes of death worldwide. As such, a vast amount of research has investigated novel therapies for preventing and/or reducing CVD. Much evidence has demonstrated the importance of dietary composition in increasing or lowering risks of CVD. While the role played by dietary n-3 polyunsaturated fatty acids (PUFAs) in reducing CVD has been recognized for many years, the protective mechanisms of these molecules, notably toward ischemia-reperfusion (IR) injury, remain unknown. Ecosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3, DHA) are two of the most important n-3 PUFAs. Both are present in fish oil. The objective of this study is to investigate the effect of acute administration of DHA on IR injury. Methods: Hearts from male C57BL6 mice were isolated and perfused in Langendorff mode and then subjected to IR injury. Hearts were perfused with different concentrations of DHA (0, 10, 50 and 100 µM) to determine its effect on cardiac function and recovery. Mechanistic studies were performed using rat myoblast cells (H9c2 cells) in an anoxia-reoxygenation protocol. Cell viability (MTT assay), cytochrome c release, and caspase-3 and caspase-8 activities were measured to compare cellular injury in DHA treated cells versus controls. The impact of DHA on mitochondrial morphology and function was assessed using epifluorescent microscopy. Results: Data demonstrated that DHA has adverse effects on both pre- and post-ischemic left ventricular developed pressures and on the heart rate, systolic and diastolic heart rates. Cell experiments revealed that significant cell death occurs in a concentration-dependent manner when H9c2 cells are treated with DHA and subjected to anoxia-reoxygenation injury. Moreover, apoptotic cell death is caused by DHA treatment, during which cytochrome c is released and caspases-8 and -3 are activated. Significant mitochondrial fragmentation and loss of membrane potential were observed with high concentrations of DHA. Conclusion: Our data suggest that acute treatment with DHA impedes the function of isolated hearts and triggers apoptotic cell death.

• Subjects / Keywords

  • H9c2 cells
  • DHA
  • Ischemia/reperfusion injury
  • Apoptosis

• Graduation date

  Spring 2013

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3ZK6P

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.