title: SEM study of adult rat hepatocytes from preneoplastic and hyperplastic foci induced in the liver by diethylnitrosamine.
abstract: Oral administration of diethylnitrosamine (DENA) at the final concentration of 70 mg/kg, 24h after partial hepatectomy induces the appearance of preneoplastic foci composed of structurally altered and enzymatic deficient liver parenchymal cells of large size. These lesions grow up and form hyperplastic nodules, 0.5 to 2mm in diameter, 9 to 10 months after DENA treatment. Adult rat hepatocytes were isolated by collagenase perfusion from treated rats, sacrificed 6 months after the carcinogen application. They were separated by elutriation in distinct subpopulations, according to cell size and degree of ploidy. Fractions elutriated at high flow rates are enriched in preneoplastic hepatocytes of large size, which display a heterogeneous distribution of microvilli. Hyperplastic nodules were examined in situ by scanning electron microscopy, in 1 to 2 mm thick tissue slices, 10 months after the carcinogen administration. The nodules, easily detected at this stage of transformation, are composed of hypertrophied hepatocytes which exhibit heterogeneous cell surfaces. The parenchymal cells reveal frequently reduced interhepatocytic faces provided with sinuous bile canaliculi and sinusoidal faces covered with closely apposed, short microvilli.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure; D004052:Diethylnitrosamine / Q000494:pharmacology*; D004195:Disease Models, Animal; D005260:Female; D006965:Hyperplasia; D008099:Liver / Q000187:drug effects / Q000648:ultrastructure*; D008113:Liver Neoplasms / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D008871:Microvilli / Q000648:ultrastructure; D009374:Neoplasms, Experimental / Q000648:ultrastructure; D009602:Nitrosamines / Q000494:pharmacology*; D011230:Precancerous Conditions / Q000648:ultrastructure*; D051381:Rats
chemical_list: D009602:Nitrosamines; D004052:Diethylnitrosamine