Early effects of chemical carcinogens as compared to induced cell proliferation. II. Automated image analysis.
Static automated image analysis was applied to study early variations of chromatin structure in Feulgen-stained liver nuclei from rats injected i.p. with a single dose of dimethylnitrosamine (DMNA), a well known hepatocarcinogen. An increase of nuclear area and a correspondent decrease of average optical density (integrated optical density/area) was observed, as compared with controls, in nuclei from rats treated with 5.4 mg/kg of DMNA. These findings, which were comparable with those induced by partial hepatectomy, indicate the existence in DMNA-treated cells of a chromatin DNA relaxation similar to the G0-G1 transition previously described for human diploid fibroblasts stimulated to proliferate. Because similar results were independently obtained by flow microfluorimetry, it seems reasonable to hypothesize that chromatin decondensation could be a prerequisite for cancer induction.
D000818:Animals; D001322:Autoanalysis; D002467:Cell Nucleus / Q000187:drug effects / Q000648:ultrastructure*; D004396:Coloring Agents; D004128:Dimethylnitrosamine / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D008115:Liver Regeneration; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012394:Rosaniline Dyes; D013194:Staining and Labeling
D004396:Coloring Agents; C007722:Feulgen stain; D012394:Rosaniline Dyes; D004128:Dimethylnitrosamine