Changes in hepatocyte ploidy in response to chromium, analyzed by computer-assisted microscopy.
Garrison-JC; Bisel-TU; Peterson-P; Uyeki-EM
Fundam Appl Toxicol 1990 Feb; 14(2):346-355
Chromium (7440473) induced changes in ploidy state were examined in mouse liver parenchyma nuclei following acute and chronic exposure to sodium-dichromate (7775113) at dose levels of 12.5 or 25mg/kg, intraperitoneally. Ploidy determination was based on a novel computer assisted microscopy system which allows rapid and accurate measurements from histological material. The animals in the acute study received the higher dose and were sacrificed at 15 minutes, 6 hours, 1, 2, 3, 4, 5, 6, or 7 days. Animals in the intermediate study were also dosed at 25mg/kg and sacrificed on days 14, 21, or 28. Those treated on a chronic basis were injected at 4 week intervals with 12.5mg/kg over a 4.5 month period for five injections prior to termination. On the basis of histological observation, chromium appeared to cause regional toxicity in the liver, primarily affecting cells in the periportal region. Chromium accelerated the normal process of polyploidization in all regions of the mouse liver. Among animals with a high proportion of diploid cells, that is the younger animals, exposure to chromium for 5 to 7 days caused a dramatic shift in ploidy, due at least partly to chromium induced cell proliferation. In an effort to develop an efficient and objective methodology for determining ploidy from histological material, the authors determined that 12 micrometer thick sections provide the best compromise thickness for dealing with sectioning and overlap problems. Several advantages were noted for the use of computer assisted microscopy for measuring ploidy.
NIOSH-Publication; NIOSH-Grant; Cell-function; Heavy-metal-poisoning; Metal-poisoning; Chromium-compounds; Chromates; Cell-damage; Laboratory-animals; Genotoxic-effects; Chromosome-damage
Pharmacology University of Kansas 39Th St at Rainbow Blvd Kansas City, Kans 66103
Fundamental and Applied Toxicology
University of Kansas Col Hlth Sci & Hosp, Kansas City, Kansas