Morphologic study of cytoskeletal systems of mouse hepatocytes using polyethylene glycol-embedding method

SM mouse livers extracted by immersion in 1% Triton X-100, or in 1% Triton X-100 followed by 0.3 M KI were studied electron microscopically using the polyethylene glycol-embedding method. After extraction with 1% Triton X-100, almost all the structural components of hepatocytes remained intact and cytoplasmic filaments could be seen three-dimensionally by using stereopairs of micrographs. It was difficult, however, to discriminate microfilaments, intermediate-sized filaments and microtubules from one anoter in these specimes . By immersion in 1% Triton X-100 followed by 0.3 M KI, hepatocytes were extracted remaining only plasma membranes, vesicles and filaments. These filaments were approximately 10 nm in diameter, that is intermediate in size. They were branched and were connected with plasma membranes, especilly at desmosomes. The combination method of immersion extraction and PEG-embedding seems to be suitable for the electron microscopic observation of the cytoskeleton of cells in situ.