Determination of isolated myocyte viability: staining methods and functional criteria.

Single ventricular cells tolerant to physiological levels of calcium have been successfully isolated from adult rat heart. These cells exhibit morphological as well as functional characteristics of the intact myocardium. Under anaerobic incubations either in the absence of extracellular calcium or in the presence of 6% PEG, myocytes excluded Trypan blue despite severe derangements in biochemical functions. We suggest that Trypan blue entry may be a rather insensitive criterion of cell injury. We recommend the combination of rod-shape morphology, ATP levels and the ability to contract under external pacing as alternative simple tests of cell viability.