[Ultrastructural changes in the hepatocytes following massive hepatectomy in rats].

This study was carried out to investigate the ultrastructural changes of the hepatocytes of the remnant liver after 70% hepatectomy in rats. The remnant liver regained the preoperative weight one week after hepatectomy. During this early posthepatectomy period, the volume of the each hepatocytes increased to a peak 48 hours after hepatectomy, then returned to normal within one week. Electronmicroscopically mitochondria of the hepatocytes became swollen and the cristae were shortened until 3 hours after hepatectomy. Dividing mitochondria were also observed in the initial 2 hours. The volume density of the mitochondria measured as a percentage of the mitochondrial volume per the cytoplasmic volume of hepatocytes. It increased and reached a peak 3 hours after hepatectomy (p less than 0.05) and thereafter returned to the same value as the control within 6 hours. Then it gradually decreased until 7th day (p less than 0.001). The volume density of lipid droplets increased to a peak 48 hours after hepatectomy (p less than 0.01). These significant ultrastructural changes of the hepatocytes indicate an important roles of mitochondria especially in the energy metabolism in the early posthepatectomy period.