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Enhanced hepatic collagen type I mRNA expression into fat‐storing cells in a rodent model of hemochromatosis
Author(s) -
Pietrangelo Antonello,
Gualdi Rossana,
Casalgrandi Giovanna,
Geerts Albert,
de Bleser Pieter,
Montosi Giuliana,
Ventura Ezio
Publication year - 1994
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840190325
Subject(s) - endoplasmic reticulum , in situ hybridization , hepatic stellate cell , cell type , hepatic fibrosis , fibrosis , immunocytochemistry , biology , microbiology and biotechnology , hepatocyte , hemochromatosis , cell , type i collagen , gene expression , northern blot , pathology , chemistry , biochemistry , endocrinology , gene , medicine , in vitro , genetics
In recent years, identifying the hepatic cell type responsible for collagen synthesis in experimental models of postnecrotic or inflammatory fibrosis has been the subject of active investigation. In primary iron overload states, however, hepatic fibrosis and cirrhosis occur without accompanying necroinflammatory phenomena. In this study, we combined morphological, immunological, cell isolation and purification and molecular biological techniques to identify the hepatic cell responsible for enhanced collagen type I gene expression during chronic enteral iron overload in the rat. Ultrastructural analysis of liver tissue sections from iron‐loaded rats specifically revealed an altered appearance of fat‐storing cells, which showed few if any fat droplets left and increased rough endoplasmic reticulum. In situ hybridization analysis with specific complementary RNA probes identified enhanced signal for collagen type I into nonparenchymal cells in zones 1 and 2, without signal over the background onto iron‐laden hepatocytes. Immunocytochemistry with desmin antibodies combined with in situ hybridization on the same tissue sections identified the cells expressing high level of collagen type I transcripts as fat‐storing cells. Northern‐blot analysis on RNA extracted from various purified cell isolates, confirmed the presence of collagen type I mRNA signal only into the fat‐storing cells isolate. Our study shows that in an experimental model of metabolic fibrosis in which the hepatotoxin selectively accumulates into parenchymal cells, fat‐storing cells are the main source of enhanced collagen type I gene expression. (Hepatology 1994;19:714–721).