[Myocardial structural proteins in cor pulmonale. Analysis by two-dimensional electrophoresis]

Changes in cardiac structural proteins caused by cor pulmonale were studied with two-dimensional electrophoresis. Sprague-Dawley rats were exposed to an oxygen-poor gas mixture (10% O2/90% N2) for three weeks. These rats (the hypoxic group) were compared to a control group that was kept in room air. Hemoglobin, hematocrit, and right ventricular systolic pressure were greater in the hypoxic group than in the control group. After the third week, desmin content of both ventricular muscles had increased in the hypoxic group, and was significantly greater in the hypoxic group than in the control group. The contents of other cardiac structural proteins did not change. These data suggest that increases in desmin are caused by adaptation of the myocardium to pressure overload associated with pulmonary hypertension. However, increases in the desmin content of the left ventricular muscle might be caused by volume overload, humoral factors, or might be a direct effect of hypoxemia.