[Ultrastructure changes of the remnant regenerating hepatocytes after partial hepatectomy in rats]

In spite of its highly functionally differentiated characteristics, the remnant liver has the capability of regeneration after massive hepatectomy either in human beings or in experimental animals. This experiment was performed to study the ultrastructural changes of the regenerated hepatocytes after massive hepatectomy. Male Wistar rats weighing around 200g were used in this study. Partial hepatectomy with resection of the median and left lateral lobes (67.31%) was performed. The rats were sacrificed at 6, 24, 48 and 72 hours after the operation. The remnant liver was inspected under a light and electron microscope. We found that: (1) the glycogen in the cytoplasm of hepatocyte nearly disappeared 6 hours after hepatectomy, with a decrease of rough endoplasmic reticulum (RER) and an increase of smooth endoplasmic reticulum (SER) and lysosomes were noted; (2) 24 hours after hepatectomy, (the nuclear membrane became zigzag shaped and the reappearance of glycogen and an increase of RER, autophagosome and lipid droplets were noted. (3) the number of mitosis increased markedly at 48 hours postoperatively; and (4) 72 hours after hepatectomy, the lysosome and RER returned to preoperative condition with some RER became dilated; SER was hardly found and lipid droplets became bigger and increased; and the nuclear membrane shape was still a zigzag at this time.