IMMUNOHISTOCHEMICAL INVESTIGATION OF TRACKS LEFT BY THE MIGRATION OF FIBROBLASTS ON TITANIUM SURFACES

Fibronectin, a major attachment protein, has been thought to be involv ed in pathway guidance, a process in which cells migrate along specifi c pathways within a tissue during development. Fibroblasts exhibit the phenomenon of contact guidance, the tendency of cells to be guided in their direction of migration by the shape of the substratum. The purp ose of our study was to test the hypothesis that fibronectin tracks ar e deposited by fibroblasts moving on smooth and grooved titanium surfa ces. The study was carried out on human gingival fibroblasts which wer e plated onto both smooth and grooved titanium substrata using medium containing either serum or fibronectin-depleted serum. The migratory p aths of the cells were determined by time-lapse photography using refl ected-light differential-interference-contrast optics. Anti-fibronecti n antibody, 1 nm gold particle conjugated secondary antibody, and silv er enhancement techniques were applied to the cultured cells, and the specimens observed in a scanning electron microscope using backscatter ed detection. By correlating the paths of the cells with the location of the fibronectin-containing material, it could be demonstrated that cells left behind fibronectin tracks on both smooth and grooved titani um surfaces. Fibronectin tracks appeared to be deposited more abundant ly by fibroblasts cultured in medium with 5% serum depleted in fibrone ctin than in complete, i.e., non-depleted, 5% serum. On the grooved ti tanium substratum, the tracks were found on the ridges as well as on t he floors and walls of the grooves. The fibronectin tracks are aligned with the grooves so that they would be expected to reinforce the cont act guidance produced by the substratum.