PERIODONTAL-LIGAMENT CELL-CULTURE ON THE HYDROPHOBIC SUBSTRATE COATEDWITH PROTEINS OF PERIODONTAL-LIGAMENT FIBROBLAST-CONDITIONED MEDIUM

In regenerating periodontal ligament (PDL) around the root of an artif icial tooth, an important role is played by some physiologically activ e substance that promotes adhesion of the cells to the surface of the tooth root and induces cell proliferation and differentiation. In this study, the supernatant of the conditioned medium (CM) of dog periodon tal ligament fibroblast (DPLF) was fractionated using an ion exchange chromatography-diethylaminoethyl (IEC-DEAE) column. DPLFs were culture d on hydrophobic dishes coated with each fraction. Cell proliferative activity and alkaline phosphatase (ALPase) activity, including electro n microscopic features of the contact surface between the cells and th e dish, were investigated. The DPLF-CM was separated by IEC-DEAE colum n into six fractions. Each fraction promoted an increase in DNA conten t and ALPase activity of the cultured DPLF, and especially remarkable were fractions 2 and 3. Fraction 2 at a molecular weight (M-w) of 210, 160, 85, 50 and 22 kD, and fraction 3 at M-w = 21 and 23 kD contained the type of proteins not found in other fractions. Electron microscop ic analysis revealed that the cells in the coating group were in close contact with the surface of the dishes and that fine fibers protrudin g from the cell membrane clinged to the dishes. In the control group, a wide gap between the cells and the dishes was observed. These findin gs suggest that the DPLF-CM fractions contain specific physiological a ctivating factors that induce proliferation and differentiation as wel l as cell adhesion of the DPLF cells.