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Updated: Oct 7, 2026
Model of Ischemia and Reperfusion Injury in Rabbits
Published on: November 3, 2023
Myocardial ischemia selectively depletes cardiolipin in rabbit heart subsarcolemmal mitochondria
E J Lesnefsky1, T J Slabe, M S Stoll
1Division of Cardiology, Case Western Reserve University, Cleveland, Ohio 44106, USA. EXL9@po.cwru.edu
Abstract:
Mitochondria contribute to myocyte injury during ischemia. After 30 and 45 min of ischemia in the isolated perfused rabbit heart, subsarcolemmal mitochondria (SSM), located beneath the plasma membrane, sustain a decrease in oxidative phosphorylation through cytochrome oxidase. In contrast, oxidation through cytochrome oxidase in interfibrillar mitochondria (IFM), located between the myofibrils, remains unaffected. Cytochrome oxidase activity in the intact membrane requires an inner mitochondrial membrane lipid environment enriched in cardiolipin. During ischemia, the content of cardiolipin decreased only in SSM, whereas the content of other phospholipids was preserved. Ischemia did not alter the composition of the cardiolipin that remained in SSM. Cardiolipin content was preserved in IFM during ischemia. Thus cardiolipin is a relatively early target of ischemic mitochondrial damage, leading to loss of oxidative phosphorylation through cytochrome oxidase in SSM.
Insights
Mitochondrial cardiolipin loss during ischemia impairs oxidative phosphorylation in subsarcolemmal mitochondria (SSM), contributing to heart injury. Interfibrillar mitochondria (IFM) remain protected, highlighting differential mitochondrial vulnerability.
Area of Science:
- Cardiovascular Science
- Mitochondrial Biology
- Ischemic Pathophysiology
Background:
- Mitochondria are crucial for myocyte injury during ischemia.
- Subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM) exhibit distinct responses to ischemia.
Purpose of the Study:
- To investigate the differential impact of ischemia on mitochondrial subpopulations.
- To identify early molecular targets of ischemic damage in cardiac mitochondria.
Main Methods:
- Isolated perfused rabbit heart model subjected to 30 and 45 minutes of ischemia.
- Assessment of oxidative phosphorylation via cytochrome oxidase activity in SSM and IFM.
- Analysis of phospholipid and cardiolipin content in isolated mitochondrial subpopulations.
Main Results:
- Ischemia significantly decreased oxidative phosphorylation in SSM but not IFM.
- Cardiolipin content specifically decreased in SSM during ischemia.
- Other phospholipids remained preserved, and cardiolipin composition in SSM was unaltered.
Conclusions:
- Cardiolipin is an early molecular target of ischemic damage in cardiac mitochondria.
- Selective cardiolipin depletion in SSM leads to impaired oxidative phosphorylation and contributes to myocyte injury.
- Differential vulnerability of SSM and IFM to ischemia is linked to cardiolipin content.
