Relationship of Mallory bodies to intermediate filaments in hepatocytes. A scanning electron microscopy study.

Livers from 12 mice fed griseofulvin for 4 to 6 months were perfused in situ with a detergent solution to extract lipid membranes leaving the cytoskeleton intact. Seven control mice were similarly studied. After 30 to 120 minutes perfusion, liver samples were examined by scanning electron microscopy and transmission electron microscopy. By light microscopy, Mallory bodies (MBs) were observed in pericentral hepatocytes. These were confirmed by transmission electron microscopy. Intermediate filaments (IFs) were observed in close apposition to MBs. Numerous IFs were seen throughout the cytoplasm. The 3-dimensional organization of the cytoskeleton and MBs were clearly visualized by scanning electron microscopy. The IFs were disorganized in the hepatocytes and formed small MBs in griseofulvin-treated mice. In the case of hepatocytes containing large MBs, there was an apparent decrease in the concentration of IFs. Transition forms of dense networks of IFs between the normal cytoskeleton and the MBs were noted in the cytoplasm between small MBs and the nucleus and also at the cell border. The IFs connected to the nucleus and invaded the MBs. The MBs appeared to form as a result of condensation or collapse of the IFs.