Extracellular matrix synthesis, proliferation and death in mechanically stimulated human gingival fibroblasts in vitro

Gingival tissues are constantly exposed to the effect of physical forces. Mechanical stimuli are regulators of connective tissue homeostasis and sustained mechanical stimulation may lead to modifications in cell activity and extracellular matrix (ECM) composition. This study examined in vitro ECM synthesis, proliferation, and death in mechanically stimulated human gingival fibroblastlike cells. Four primary human cell strains were established and subjected to intermittent stretching in FX-3000 Flexercell Strain Unit for 10 days, 45 min/day, at 1 Hz, 10% strain, and cell proliferation, cell death, and synthesis of collagens types I, III, and V, matrix metalloproteinase 1, elastin, and tenascin were assessed. In some of the cell strains mechanical stimulation led to changes in synthesis of the ECM molecules, proliferative activity, and death of stimulated cells as shown by statistically significant differences between the experimental and unstimulated control cultures. Although not seen in every culture investigated, these findings suggest that prolonged mechanical stimulation might lead to conspicuous modifications in the metabolic activity of gingival fibroblasts and cause changes in the ECM composition of the gingival connective tissue. The results indicate a pronounced interindividual variation in reactions of gingival fibroblasts to mechanical stimulation.