A Quantitative Stereological Description of the Ultrastructure of Normal Rat Liver Parenchymal Cells

Abstract

The principles of stereology have been applied to a morphometric analysis of parenchymal cells from the peripheral, midzonal, and central regions of normal rat liver lobules. The fractional volumes of cytoplasm occupied by mitochondria, peroxisomes, lysosomes, lipid, and glycogen have been determined. The surface densities of smooth-and rough-surfaced endoplasmic reticulum and of mitochondrial envelope and cristae have also been measured. The average number and dimensions of mitochondria and peroxisomes have been evaluated. By the use of an independent measurement of the average cytoplasmic volume, these data have been expressed as the actual volumes, areas, and numbers per cell in the different parts of the hepatic lobule. Similarly, the volumes of the envelope, cristae, and matrix compartments and the area of cristae membranes have been calculated for the average-sized mitochondrion in each lobular zone. Structural homogeneity is found in over 80% of normal rat liver parenchymal cells, with most of the significant differences being confined to those cells immediately surrounding the central veins.

Intergrated stereological and biochemical studies of hepatocytic membranes. I. Membrane recoveries in subcellular fractions

“…This analysis of model systems has shown that some of the previous concepts of section thickness effects have had to be revised. Loud (21) had reasoned that membrane systems such as cisternae of ER or mitochondrial cristae should be underestimated, because the difficulty of recognizing obliquely sectioned elements should lead to a "loss" of up to 1/3 of the membrane; in an earlier study from this laboratory (35), this concept was adopted although the loss was considered somewhat less important. This notion must be revised: First, considerations on the geometric probability of sectioning have revealed grazing sections of ER cisternae or cristae to be relatively rare events; secondly, the use of en bloc staining with uranyl acetate enhances the contrast so that obliquely sectioned membranes are still recognized to a large extent particularly if the analysis is done at high magnification, as in the present study.…”

Cytomorphometry of Developing Rat Liver and Its Application to Enzymic Differentiation

“…The principles involved in the quantitative, stereological, or morphometric analysis of tissues have been described recently (3,4) . The fraction of tissue volume occupied by component i (V" ') is proportional to the fraction of the area (of a thin section) occupied by this component .…”

“…Several enzymes which emerge during late fetal or neonatal life remain constant per gram (i .e ., increase per cell) during the postnatal doubling of the parenchymal cell volume (e .g ., glycogen synthetase, tyrosine aminotransferase, and glucokinase in Figs . [4][5][6], suggesting that they are concerned with the maintenance of cytoplasmic functions . On the other hand, enzymes which are high in fetal liver and may be necessary for proliferation might be expected to remain low per cell after the establishment of minimal rates of mitosis .…”

“…Cytomorphometry, utilizing thin sections obtained from tissue with well-preserved three-dimensional structure, is a method of choice for determining the cellular composition of the tissue from which such homogenates are prepared . The present study applied the recently described methods of quantitative stereology (3,4) to determine the cellular composition of rat liver during development and to test the extent to which it may change upon the administration of hormones which are known to promote enzymic differentiation .…”

Morphologic and Biochemical Changes in Dogs After Portacaval Shunt Plus Bile Fistula or Ileal Bypass: Failure of Bile Fistula or Ileal Bypass to Prevent Hepatocyte Atrophy

“…The size of the midzonal hepatocytes before and after PCS were determined by tracing large numbers of liver cells on standard thickness paper, cutting out the silhouettes, and weighing them (9). Midzonal hepatocytes identified in half-micron Epon sections were also used for measuring on electron micrographs the area of rough and smooth endoplasmic reticulum within these cells and the dimensions of mi- (15). Autoradiography was performed on dewaxed paraffin sections of liver using Ilford K2 nuclear emulsion.…”