Effects of colchicine on periodontal ligament fibroblasts of the mouse: I. Ultrastructural study of the disruption of microtubule‐dependent cellular functions

The effects of colchicine administration on the ultrastructure aad function of periodontal ligament fibroblasts was studied in young mice as a further attempt to document the microtubule‐dependent nature of collagen secretory granule translocation. Disruption of the normal appearance of the Golgi complex was an early response to colchicine administration. This change was visible at the light microscopic level. At the electron microscopic level it was observed that Golgi saccules were dispersed and that Golgi cisternae were shorter and reduced in number. Microtubules were absent. Dense granules accumulated in a juxtanuclear region of cytoplasm previously occupied by the normal Golgi complex. Lipid droplets and autophagosomes were increased in number. Intermediate filaments (10 nm diameter) formed perinuclear fascicles several hours after colchicine treatment. These results as well as the recently published report (Cho & Garant 1981d) support the concept that microtubules play an important role in the normal organization of the Golgi complex and in the translocation of secretory granules to the fibroblast cell surface.