Development of vimentin filaments in the cells of the articular disc of the rat squamosomandibular joint with age

Age-related changes in the vimentin filaments were studied by immunohistochemistry and electron microscopy. In 2-week-old rats, cells showed only weak labelling for vimentin. A few intermediate filaments but well-developed rough endoplasmic reticulum and Golgi apparatus were observed in the cytoplasm. As the age of the rats advanced from 4-weeks to adulthood, labelling intensity increased and the cytoplasm of articular-disc cells was gradually filled with intermediate filaments surrounding degraded cytoplasmic organelles in the cytosol. Articular-disc cells in adult rats showed intense vimentin labelling and their cytoplasm was filled with closely packed intermediate filaments aligned in alternating layers. This age-related accumulation of vimentin filaments in articular-disc cells may be an adaptive response to compressive forces.