Structural Changes Of Myocardium Under Modeling Of Cardiomyopathy And Its Correction With Stem Cells In Animals Of Different Age

This study aimed to investigate the age- related structural and ultrastructural changes and the level of apoptosis (TUNEL assay) in mice myocardium (5 and 25 mo.) after administration of Isoproterenol (IP) (100 mg/kg body weight, 5 days) and further transplantation of stem cells - mice bone marrow- derived mononuclear cells (BM-MNCs) (5 mil.). IP administration created cardiac hypertrophy in experimental animals. Heart weight/body weight ratios (HW/BW) increased significantly, compared to sedentary animals for both young (33 %) and old (11 %) mice. Cell cross-sectional area in H&E stained sections was also significantly increased in mice treated with IP; cardiomyocytes (CMC), as well as myocytes in arteriole wall appeared to be thicker. Besides there developed fibrosis and numerous focal injuries (with dystrophic and destructive changes in CMC and capillaries) predominantly in the left ventricle and septum wall that appeared to be more severe in old animals. Transplantation of BM- MNCs to the animals with IP-induced cardiomyopathy has produced definite normalizing effect on CMC and capillaries structure, being more pronounced in the young mice. The latter displayed HW/BW decrease and less marked dystrophic and necrotic changes in CMC as well as the lower amount of the injury foci. Besides, it is shown the apoptotic level decrease predominantly in the young animals. The apoptotic index in these animals was almost two-fold lower while it remained almost unchanged in the old ones.