[Malignant tendency of basophilic liver cells in experimental rat hepatocarcinogenesis]

To investigate the malignant tendency of liver basophilic cells in rats by examining the liver dynamic pathological changes during the hepatocarcinogenesis induced by diethylnitrosamine (DEN).

One hundred forty male Sprague-Dawley rats, about 200 g each, were randomly divided into a normal group and a model group. The model group rats were administered 1% DEN intragastrically once a week for 14 weeks. The normal control group rats were given saline instead of DEN. Seven to ten rats of the model group were sacrificed at 2, 3, 5, 8, 10, 12, 14, 18 weeks. The remaining rats were followed to the end of the experiment at 26 weeks. Histopathological changes of the livers were analyzed, and the localization of GST-P and PCNA in the livers were detected in situ by immunohistochemistry.

According to the characteristics of the lesions in the model group, histological liver change patterns were categorized into three phases: (1) liver injury phase (2 to 5 weeks) with centrilobular necrosis, a small amount of collagen deposition in the necrotic regions with fibrous septa development and cell proliferation; (2) the cirrhosis phase (8 to 12 weeks) with significant hepatocellular regeneration and collagen deposition. As the regenerative nodules and fibrous septa formed, cirrhosis with uniform sized nodules developed in all the rats at 12 weeks. In the regenerative nodules, significant hepatocellular metamorphosis was seen; (3) In the carcinomatous transformation and nodular remodeling phase (after 14 weeks), two types of cancer, namely hepatocellular carcinoma and cholangiocarcinoma were found. Incidence of the cancer was 62.5% at 18 weeks. Basophilic cell lesions appeared beginning at 10 weeks. Pale bodies were seen in some basophilic cells. Small cell changes appeared starting at 12 weeks. Some of these cells containing droplets like lipid vacuoles, invaded into the surrounding liver tissues. Both basophilic cell lesions and small cell changes were all positive for proliferating cell nuclear antigen (PCNA).

Development of foci of basophilic small cells, with cells containing lipid vacuoles and pale bodies, and invading into the surrounding liver tissues are the changes highly suggestive of an early hepatocellular carcinoma transformation.