Hepatic nuclear ploidy distribution of dietary-restricted mice.

Abstract

Hepatic parenchymal cells in most adult mammals are polyploid, with most of the cells in the quiescent or low-proliferation state. Polyploidization has been related to carcinogenesis and aging, and both end points are significantly affected by dietary restriction (DR). Direct measures of hepatic nuclear polyploidization in DR B6C3F, mice have not been examined. We examined the effect of DR on distributions of nuclear ploidy in both sexes and on different age groups of R6C3F, mice. Differences between young and old male mice and between old male and female mice were also compared. Hepatic nuclear ploidy values were measured by flow cytometry. The DNA histograms were analyzed for the percentage of nuclei having different classes of DNA content by gating channels between the areas under the peaks of diploid, tetraploid, and octaploid. The results indicate that 1 or 26 months of DR started at 4 months of age did not alter hepatic nuclear ploidy distributions in young and old mice. Our data suggest that in the male mouse, polyploidization is established by 5 months of age for hepatic nuclei and that ploidy classes are affected by sex at 30 months of age. For females, effects in the octaploid nuclei are seen as a result of DR.

The Toxicokinetic Profile of Dex40-GTMAC3—a Novel Polysaccharide Candidate for Reversal of Unfractionated Heparin

“…Some hepatocytes showed enlargement of both hepatocyte cytoplasm and nuclei, not typically seen in control mice. Spontaneous occurrence of karyocytomegaly is more common in aging mice than in rats (Lu et al, 1993 ; Styles, 1993 ) and it is not typically associated with increased liver weight. We did not observe such changes in rats.…”