Selective killing of fibroblast-like cells in cultures of mouse heart cells by treatment with a Ca ionophore, A23187

Myocardial cells uncontaminated by fibroblast-like cells could be obtained by treating mouse heart cell cultures with a Ca ionophore, A23187. When trypsin-dissociated mouse heart cells were cultivated for 1 day or more on Petri dishes, both myocardial and fibroblast-like cells were detected on the dish under a phase contrast microscope. However, when the cultured heart cells were treated for a short period (e.g. 10 min) at 25 °C with A23187, only fibroblast-like cells exhibited morphological degeneration, such as nuclear pycnosis, cytoplasmic condensation and bleb- and balloon-formation. The myocardial cells maintained their normal morphology during the treatment; transient irregular beating was observed, but disappeared after removal of A23187. Thus treatment of heart cell cultures with A23187 can yield a large amount of myocardial cells without contamination by fibroblast-like cells. The possible mechanism for this selective effect is discussed.