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Membrane alterations in acute myocardial ischemia
Canadian Journal of Biochemistry
|October 1, 1980
Summary
Acute myocardial ischemia in rabbits damages heart cell membranes and mitochondria. Sarcolemmal Na+,K+-ATPase activity loss indicates irreversible damage, useful for evaluating drug interventions.
Area of Science:
- Cardiovascular Biology
- Cellular Biochemistry
- Ischemic Heart Disease Research
Background:
- Acute myocardial ischemia leads to cellular damage.
- Understanding molecular changes in subcellular organelles is crucial for assessing cardiac injury.
Purpose of the Study:
- To investigate the molecular consequences of acute myocardial ischemia on subcellular organelles in rabbit hearts.
- To identify sensitive biochemical markers of irreversible myocardial damage.
Main Methods:
- Induction of acute myocardial ischemia by ligating the left circumflex coronary artery in rabbits.
- Assessed biochemical properties of mitochondria, sarcolemma, and lysosomes.
- Measured enzyme activities (e.g., ATPase, cytochrome c oxidase) and cellular ATP levels.
- Analyzed protein profiles and membrane lipid ratios.
Main Results:
- Mitochondrial ATPase activity decreased early (5 min), but cytochrome c oxidase remained unchanged.
- Sarcolemmal Na+,K+-ATPase inactivation mirrored mitochondrial ATPase loss and was irreversible upon reperfusion.
- Cellular ATP levels decreased and remained depressed post-reperfusion.
- Lysosomal enzyme latency decreased later than sarcolemmal/mitochondrial alterations.
- No changes in protein electrophoretic profiles or key membrane lipid ratios were observed.
Conclusions:
- Sarcolemmal Na+,K+-ATPase serves as a sensitive index of irreversible myocardial necrosis.
- This enzyme's activity can be a valuable tool for assessing the efficacy of pharmacological interventions against ischemic injury.