[Ultrastructural stereologic study of cardiac muscle cells during myocardial atrophy].

Wistar rats were exposed to complete starvation over 2, 5 and 10 days. In the course of the experiment the animals developed general atrophy associated with myocardial atrophy. They showed also diminution of the absolute weight of the heart and the diameter of cardiomyocytes. The volumetric and surface density of cell structure were detected stereologically by electron microscopy to evaluate the volumetric and surface-volumetric ratio of the main organellas. It was demonstrated that the volumetric density of mitochondria diminishes in myocardial atrophy while the relative amount of myofibrils increases. The surface density of mitochondria is maintained at the same level as that seen in the control and declines by the end of the experiment. The myocardial atrophy was stereologically ascertained by the volumetric ratio of mitochondria to myofibrils and by that of the T system to myofibrils. This ratio becomes the lesser the higher the degree of atrophy.