Chemotactic response of periodontal ligament cells decreases with donor age: Association with reduced expression of C-fos

OBJECTIVE: To understand the effects of aging on cellular motility of human periodontal ligament (PDL) cells, and to determine the possible link between cell proliferation and migration in relation to cellular aging. MATERIALS AND METHODS: The chemotactic response of PDL cells from three juvenile and four older donors were compared. Then, migrated or unmigrated cells were examined for their cell cycle by morphological and immunocytochemical procedures. Finally, migrated or unmigrated cells were examined for the expression of c-fos and c-myc by in situ hybridization. RESULTS: PDL cells from older donors showed lower chemotaxis compared with the cells from juvenile donors (P < 0.05). Cells undergoing migration were found not to be in the S- or M-phase of the cell cycle. However, all migrated cells were found to express c-fos, while many of the cells which did not migrate were found not to express c-fos. CONCLUSIONS: Cellular motility of PDL cells decreases with donor age as well as cell proliferation. Since the cells reaching senescence fail to express c-fos, the mechanisms linked to cellular senescence may be a possible underlying mechanism for low migration seen in the older cells.