Myocardial ischemia damages cardiac myocytes in part via opening of the mitochondrial permeability transition pore. Preventing this pore's opening is therefore a useful therapeutic goal in treating cardiovascular disease. Hydroxysafflor yellow A has been proposed as a nontoxic alternative to other agents that modulate mitochondrial permeability transition pore opening. In this study, we proposed that hydroxysafflor yellow A prevents mitochondrial permeability transition pore formation in anoxic cardiac myocytes, and thus protects the cell from damage seen during reoxygenation of the cardiac myocytes. Experiments with hydroxysafflor yellow A transport in aerobic myocytes show that roughly 50% of the extracellular dye concentration crosses the cell membrane in a 2-h incubation. In our anoxia/reoxygenation protocol, hydroxysafflor yellow A modulated both the reduction of viability and the loss of rod-shaped cells that attend anoxia and reoxygenation. Hydroxysafflor yellow A's protective effect was similar to that of cyclosporin A, an agent known to inhibit mitochondrial permeability transition pore opening. In additional experiments, plated myocytes were loaded with calcein/MitoTracker Red, then examined for intracellular dye distribution/morphology after anoxia/reoxygenation. Hydroxysafflor yellow A-containing cells showed a cardioprotective pattern similar to that of cyclosporin A (an agent known to close the mitochondrial permeability transition pore). We conclude that hydroxysafflor yellow A can enter the cardiac myocyte and is able to modulate anoxia/reoxygenation-induced damage by interacting with the mitochondrial permeability transition pore.

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