[Tissue stereological analysis of myocardial atrophy during hypokinesia]

The myocardium of Wistar rats which were in a state of hypokinesia for 5, 15 and 30 days was assayed morphologically. Morphometric and stereological methods were used to measure the diameter of cardiomyocytes, the volume and surface densities of muscle fibers and interstitial connective tissue. Myocardial atrophy (absolute heart weight loss, reduction in the cardiomyocyte diameter) was shown to develop in the course of hypokinesia. Informational analysis revealed the increased enthropy and relative enthropy as well as reduction of excess myocardial tissue. Long-term immobilization also resulted in an increase of the relative volume density of the stroma, collagenization of the interstitial connective tissue, and marked tendency toward diminution of the surface-volume ratio of the capillaries.