Article révisé par les pairs
Résumé : Adult rat hepatocytes, from control and N-nitrosomorpholine (NNM) treated rats, were isolated by enzymatic perfusion in presence of collagenase and hyaluronidase and maintained in suspension by using a gyratory shaker. Five hepatic subpopulations were spearated by elutriation, in both experimental models, according to cell size and ploidy. A first fraction (I) contains mainly small diploid cells (mean diameter : 17.5 μm ± 0.3); fractions II and III are composed of tetraploid cells (mean diameter : 20 and 21 μm ± 0.2), while fractions IV and V present hepatocytes of large size (mean diameter : 23.8 μm ± 0.3) and doublets of undissociated cells. The elutriation process demonstrates the high proportion of large hepatocytes present after the carcinogenic treatment. Fractions IV and V are enriched in large hyperplastic cells, still contaminated by doublets. For scanning electron microscopy, isolated and elutriated parenchymal cells from normal and NNM treated rats, were fixed in cacodylate buffered glutaraldehyde at the final concentration of 2.5%, for 24 h, harvested in monolayer distribution onto Flotronics silver membranes, dehydrated in acetone and critical point dried, using CO2. Elutriated hepatocytes from control rats exhibit numerous regularly distributed microvilli, which covered the entire cell surface. Hyperplastic parenchymal cells from NNM treated rats present irregular contours and display numerous microvilli which are heterogeneous in size and distribution.