A comparison of the effect of epidermal growth factor, platelet-derived growth factor and fibroblast growth factor on rat periodontal ligament fibroblast-like cells
The purpose of this study was to examine the morphology, growth pattern, and DNA synthesis of rat periodontal ligament fibroblast-like cells in the presence or absence of recombinant epidermal growth factor (rEGF), natural platelet-derived growth factor (nPDGF), and natural fibroblast growth factor (nFGF), under the same conditions and with special reference to high concentrations of growth factors. Growth factors were obtained from different chemical companies (rEGF=1.0 to 10,000 ng/ml, nPDGF.5 to 50 ng/ml, and nFGF 1.0 to 1,000 ng/ml). For the cell line, fibroblast-like cells from periodontium of rats were cultured. The study of the morphology and the growth pattern was performed in the presence of serum (to assure vitality of cells).The parameters used were adherence/non- adherence, mono/multilayer, presence of foci, organized or random cell orientation, homogeneous or heterogeneous cell distribution, cell form, and nucleus form. Cells were seeded to the culture and incubated for 24 hours. Then cultures were rinsed and serum deprived for 48 hours before the medium was changed to a serum-free growth medium supplemented with growth factors. Mitogenic effect was monitored 18 hours later by labeling it with 3H thymidine: rEGF was used as (+) control (it was only able to mediate a limited effect on 3H thymidine, based on a previous study). When comparing growth and morphology patterns, no differences were found between cultures exposed to growth factors. In DNA synthesis there was a mitogenic effect of rEGF, nPDGF, and nFGF on periodontal ligament fibroblast-like cells. Incorporation of thymidine in each case showed a dose-dependent relationship with the concentration of the growth factor. The maximum effect was 131% for rEGF, 274% for nPDGF, and 182% for nFGF. The optimal mitogenic concentrations were as follows: 1 to 100 ng/ml for nFGF, .1 to 1 for rEGF, and .1 to 15 ng/ml for nPDGF (half maximum stimulation rEGF=.75, nPDGF=2.5, and nFGF=8). In conclusion, rEGF, nFGF, and nPDGF are mitogenic agents for rat periodontal ligament fibroblast-like cells. The results of this study strongly suggest that growth factors may have a major impact on fibroblast-like cells in the periodontal ligament. [c.c.]
Biom, S., P. Holmstrop, and E. Dabelstleen, J Periodont, 65:373, 1994