The intermediate filaments in human hepatocytes.

The intermediate filaments (IFs) in human hepatocytes were studied in biopsy specimens from patients with minimal histological changes. They were clearly visualized three-dimensionally by using polyethylene-glycol-embedding method after washing out cellular organelles and other components of cytoskeletons with a solution containing 0.15% Triton X-100 and saponin 0.5 mg/ml. We demonstrated that IFs were distributed throughout the cytoplasm in a meshwork fashion, attached to the junctional complex, encircled the bile canalicular lumen, and were directly attached to nucleus. Even after extensive washout of cytoplasmic structures, hepatocytes did not collapse, with the nuclei situated at due places in the cells. These findings may support the view that IFs play a role in nuclear positioning and in keeping the cytoplasmic space in human hepatocytes.