Cellular mechanisms of rat liver regeneration after experimental myocardial infarction

Morphological changes and regeneration activity of rat liver after experimental myocardial infarction (MI) caused by a permanent left coronary artery occlusion were investigated. It was shown that, 6 months after MI, considerable changes were observed in the rat liver circulatory system: the vessel amount per unit area increased by 118%, the thickness of their walls increased by 19%, and the average area of vessel lumens increased by 159%. The contribution of connective tissue 6 months after MI increased by more than one- and-a-half times in comparison with control. Inflammatory and necrotic changes in rat liver remained for 6 months after MI. The liver injury caused by MI leads to activation of regeneration processes in its parenchyma. Six months after MI, the number of 4c-hepatocytes decreased by 12% in comparison with control and the number of 4c×2- and 8c-hepatocytes increased by 45 and 71%, respectively. Six months after MI, the hepatocyte ploidy increased by 11%. In this period, the dry mass of rat hepatocytes increased by 19%. Thus, liver regeneration after MI is stipulated by hepatocyte hypertrophy rather than their polyploidization.