Increase in Hepatocyte and Nuclear Volume and Decrease in the Population of Binucleated Cells in Preneoplastic Foci of Rat Liver: A Stereological Study Using the Nucleator Method

Abstract

Gamma-glutamyltranspeptidase-positive hepatocyte foci were produced in female rats given a single dose of diethylnitrosamine neonatally after birth and, after weaning, a diet containing phenobarbitone for 30 wk. The nucleator method, a new stereological approach, provided an efficient, unbiased estimate of mean cell volume in focal lesions and extrafocal areas. It also provided an unbiased sample of cells to estimate hepatocyte nuclear volume and the percentage of binucleated cells. The results showed an increase in the mean volume of mononucleated cells--from 4,700 micron3 in extrafocal areas to 12,700 micron2 in foci--and of binucleated cells--from 6,900 micron3 to 25,000 micron3. This demonstrated the hypertrophic effect of the carcinogenic treatment in focal lesions. A striking reduction in the proportion of binucleated cells was also observed in the preneoplastic lesions. Nuclear volume measurements from mononucleated and binucleated hepatocytes were used to assess ploidy. An apparent increase in nuclear ploidy, with no change in cellular ploidy, was noted in focal tissue when compared with nonfocal tissue. This appeared to be caused by an increase in mononucleated tetraploid cells and a reduction in binucleated cells with two diploid nuclei, indicating an altered mitotic mechanism in focal lesions. The significance of these changes in cell volume, apparent ploidy levels and binuclearity in preneoplastic foci is discussed in relation to the hepatocarcinogenic process.

Stereological Challenges When Working With Heart Muscle Fibres

“…All myocytes were followed in both directions until they disappeared (at a magnification of ×749), and the number of nuclei per myocyte was counted (Jack et al, 1990), as shown in Fig. 3.…”

Ultrastructural changes in chemically induced preneoplastic focal lesions in the rat liver: a stereological study

“…The sections were mounted on 200 mesh copper grids which were coated with a carbon-coated parlodion film, and stained with 5% uranyl acetate and Reynolds lead citrate. The remaining tissue in the block was used for LM to estimate the mean hepatocyte volume (12).…”

“…The mean volume (V) and the mean surface area (S) of each compartment per hepatocyte were calculated by multiplying the volume ratio and surface ratio respectively by the mean hepatocyte volume (the reference space volume) which was estimated independently in a parallel study (12).…”

“…The mean hepatocyte volume was estimated at the LM level using hepatocytes sampled from semi-thick sections which were taken from the same tissue blocks as the ultra-thin sections (12).…”

“…Changes in the ploidy levels and in the percentage of binucleated cells, in response to the mitogenic effect of PB in DENA-initiated focal lesions, have been recently reported (12). The effect of PB as a stimulator of cellular hypertrophy in the foci was also assessed, revealing a marked increase in mean hepatocyte volume (12).…”