Relationship between cytoskeleton and desmosome in the primary cultured hepatocytes

We evaluated interrelationship of cytoskeleton (CS) and desmosome (DS) in primary cultured hepatocytes using CS disrupting agents. After 24 hrs incubation of rat hepatocytes, the mediums were exchanged to the medium containing colchicine (Co) and/or cytochalasin D (CD). The fluorescence microscopy was performed for cytokeratin (CK), desmoplakin (DP), tubulin (Tu) and F-actin. Immunoelectron microscopy was done to observe intermediate filaments (IFs) and DSs. In the Co treated cells, microtubules disappeared and Tu was diffusely stained but other CSs and DP were not changed. In the CD treated cells, the disrupted actin bundles formed aggregates, where fluorescence labeling DP often coexisted and the distribution of CK was slightly altered. In the cells treated with Co and CD, the attachment of hepatocytes became loose, in which the distribution of CK in their cytoplasm appeared heterogeneous. Ultrastructural study revealed that the aggregation of actin might result in the concentration of IFs and gold particles labeling DP often coexisted in the aggregates. Our results indicate that IFs are connected with microfilaments with the aid of DSs in the cell periphery and microtubules contribute to the distribution of IFs in the cytoplasm.