[Regeneration of liver parenchyma and sinusoidal cells following partial hepatectomy]

Partial hepatectomy (30 percent of the liver weight) was performed in 225 female Wistar rats, ages 6 weeks, 6 and 9 months. The animals were sacrificed in intervals between 4 hours and 21 d after the operation. The automated microscopic image analysis after Simon et al. (1984) and histoautoradiography were utilized for evaluation of liver cell regeneration. Despite measurement of more than 1,000 cells per animal we were not able to confirm enlargement of hepatocytes as the first reaction to partial hepatectomy The number of liver cells per unit area increased whereas sinusoidal size remained rather constant, corresponding to a decrease in average cell size and in the standard deviation of cell area. The importance of binucleated hepatocytes in the process is emphasized. Measurement of the nucleoli and of the mean extinction values of liver cell nuclei as a measure of the DNA content did not provide any essentially new perspectives. The investigation did however emphasize the importance of the extent of the hepatic resection and the age of the experimental animals on the intensity and subsequent course of liver cell regeneration. Proliferation of the sinusoidal cells themselves after partial hepatectomy could not definitively be demonstrated to be age-dependent.