Naramoto A, Ohno S, Furuta K, Itoh N, Nakazawa K, Nakano M, Shigematsu H
Department of Pathology, Shinshu University School of Medicine, Matsumoto, Japan.
Hepatology. 1991 Feb;13(2):222-9.
We observed hepatocyte cytoskeletons in phalloidin-treated 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.
我们采用快速冷冻和深度蚀刻法在三维空间观察了用鬼笔环肽处理的大鼠的肝细胞细胞骨架，并将其与传统超薄切片的超微结构结果进行了比较。用鬼笔环肽处理1周的大鼠，扩张胆小管中的微绒毛数量减少。在肝细胞中，胆小管周围的细胞质可分为三层，即微丝增多层、分泌系统细胞器层和平滑面内质网增多层。用鬼笔环肽处理4周的大鼠，除了大溶酶体和微管数量增加外，微丝还延伸到细胞核附近的细胞质中。在两组中，通过快速冷冻和深度蚀刻法都可以在胆小管周围和细胞边界处观察到微丝的三维结构。直径为7至10纳米的分支微丝直接附着在其他细丝、细胞器或细胞膜的细胞质侧。此外，在与长期胆汁淤积相关的胆小管周围微丝周围，成束的中间丝增多。提示胆小管周围微丝的过度积累会干扰胆汁成分向胆小管的分泌。中间丝的细胞骨架重组似乎会改变各种细胞器的排列。
