Cardiomyocyte Apoptosis Induced in Langendorff Preparation of Isolated Guinea-Pig Heart Perfused with Krebs-Henseleit Solution Deprived of Glucose, with and without Oxygen Supply

Whether or not deprivation of glucose and oxygen can induce cardiomyocyte apoptosis was examined. Four groups of Langendorff preparations of guinea-pig hearts were perfused for 6 h with Krebs-Henseleit (K-H) solution deprived of glucose (group A), deprived of oxygen (group B), and deprived of both glucose and oxygen (group C), then examined for the mode of myocardial cell death. The control was perfused with K-H solution. Results: In group A, myocardial cell death by apoptosis and necrosis was induced. In group C, the apoptotic lesion induced was exaggerated compared to that produced by glucose deprivation alone. In group A and C, decreases in intracellular ATP (ATPi) and intracellular acidosis were observed. In group B and the control, myocardial cells survived with spotted necrotic foci without myocardial-cell apoptosis. A mild decrease in ATPi was observed. However, intracellular pH did not shift to acidity (7.0-7.2). Conclusion: Myocardial cell apoptosis was not induced by a 6-h stimulus of oxygendeprivation (hypoxia) alone, but rather by a 6-h stimulus of glucose-deprivation with or without an oxygen supply. Deprivation of both glucose and oxygen intensified the apoptotic lesion. Apoptosis coincided with a decrease in the levels of ATPi and intracellular acidosis.