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Ultrastructural studies of hepatocyte cytoskeletons of phalloidin‐treated rats by quick‐freezing and deep‐etching method
Author(s) -
Naramoto Atsuhiko,
Ohno Shinichi,
Furuta Kiyoshi,
Itoh Nobuo,
Nakazawa Koh,
Nakano Masayuki,
Shigematsu Hidekazu
Publication year - 1991
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.1840130205
Subject(s) - phalloidin , ultrastructure , hepatocyte , microbiology and biotechnology , chemistry , etching (microfabrication) , biophysics , cytoskeleton , anatomy , materials science , biology , cell , nanotechnology , biochemistry , layer (electronics) , in vitro
We observed hepatocyte cytoskeletons in phalloidintreated rats by the quick‐freezing and deep‐etching method in three dimensions and compared them with the ultrastructural findings on conventional ultrathin sections. The numbers of microvilli in dilated bile canaliculi were decreased in the rats treated with phalloidin for 1 wk. In hepatocytes the cytoplasm around bile canaliculi could be divided into three layers, increased microfilament layer, cell organelle layer of secretory system and increased smooth surface endoplasmic reticulum layer. In the rats treated with phalloidin for 4 wk, microfilaments were extended into the cytoplasm near the nucleus in addition to the increased number of large lysosomes and microtubules. In both groups, three‐dimensional structures of microfilaments could be visualized around bile canaliculi and along cell borders by the quick‐freezing and deep‐etching method. The branching microfilaments with the diameters of 7 to 10 nm were directly attached to other filaments, cell organelles or cytoplasmic sides of cell membranes. Moreover, bundled intermediate filaments were increased around peribiliary microfilaments associated with long‐term cholestasis. It is suggested that excessive accumulation of peribiliary microfilaments disturb the secretion of bile components into bile canaliculi. The cytoskeletal reorganizations of intermediate filaments seem to alter the arrangements of various cell organelles. (H EPATOLOGY 1991;222–229).