IMPROVED ISOLATION OF CARDIOMYOCYTES BY TRYPSINATION IN ADDITION TO COLLAGENASE TREATMENT

The present study was undertaken to develop an improved and stabilized method for isolating cardiomyocytes from perfused rat heart. Differen t lots of the commercial collagenases used for isolating cardiomyocyte s give variable results both with respect to the total cell yield and the percentage of elongated cells obtained. When trypsin was present b oth before and during collagenase treatment of the tissue, the perform ance of the collagenases was improved and stabilized, and a high and s table cell yield (7.5x10(6) cells per heart), and a high percentage of elongated cells (about 70%) was regularly obtained. The cells posesse d alpha(1)-adrenergic binding sites with binding properties (B-max=43. 5 fmol/mg protein and K-d=125.5 pmol/l) in agreement with values previ ously reported. The cells were able to respond functionally, as the ce llular uptake of Rb-86(+) increased by 18% after alpha(1)-adrenoceptor stimulation with phenylephrine. These criteria indicate that the cell s were well preserved during the isolation procedure.