Laboratory of Cytology and Cellular Biology, Institute of Regional Pathology and Pathomorphology, Siberian Division of Russian Academy of Medical Sciences, Novosibirsk.
Remodeling of the myocardium in Wistar rats during aging is characterized by cardiomyocyte hypertrophy and increase of their total volume in the left ventricle; the total volume of the connective tissue also increases without marked changes in cardiomyocyte count and total volume of blood capillaries. The number of cardiomyocytes with contracture injuries of different severity in the myocardium of aging animals increases against the background of hemodynamic disorders. At the cellular level, compensatory hypertrophy of cardiomyocytes during aging is characterized by a pronounced increase in the myofibril bulk paralleled by relative deficiency of the mitochondria and pronounced deficiency of agranular sarcoplasmic reticulum and T system, involved in the regulation of intracellular Ca2+.