MORPHOMETRIC ANALYSIS OF CULTURED NORMAL AND CARDIOMYOPATHIC HAMSTER HEART-CELLS AFTER IMMUNOFLUORESCENT STAINING FOR TUBULIN AND ALPHA-ACTININ

The cardiomyopathic (CM) hamster (Strain UM X7.1) develops a progressive cardiomyopathy characterized by cellular necrosis, hypertrophy and congestive heart failure. To better understand these abnormalities, this study was undertaken to investigate possible abnormalities in the morphology and distributions of cytoskeletal proteins in normal and cardiomyopathic hamster heart cells in vitro. Primary cultures of cardiac myocytes from normal and CM newborn hamsters were analyzed and compared by indirect immunoflorescent microscopy after 3, 5, 7 and 9 days in culture. The distributions of the cytoskeletal proteins, a-actinin and tubulin, were examined in cultured hamster cardiac myocytes. After the cells attach to coverslips, both normal and CM myocytes appear rounded in shape. After 5 days in culture: CM myocytes show fewer cytoplasmic projections than normal. To assess this phenomenon, the area and perimeter dimensions of normal and CM myocytes were analyzed by morphometric methods. It was determined that cardiomyopathic cells in culture become progressively larger in area but smaller than normal in their perimeter dimensions. A statistically significant difference was noted from day 3 onward. This result confirms that cardiomyopathic cells have abnormal shapes in vitro. It is conceivable that a reduction of the perimeter dimension in CM cells may be related to the reported calcium overload or to other biochemical or physiological lesions. In addition, the greatest density of tubulin staining is present immediately around the nucleus, with fluorescent ''rays'' radiating out to the cell periphery. Most of the myofibrils labelled by anti-a-actinin antibody showed parallel arrangements with respect to each other in normal myocytes whereas in CM heart cells the myofibrils were disarrayed. There were no differences in the distributions of tubulin and alpha-actinin in normal and cardiomyopathic myocytes in culture.