MECHANICAL-STRESS INDUCES DNA-SYNTHESIS IN PDL FIBROBLASTS BY A MECHANISM UNRELATED TO AUTOCRINE GROWTH-FACTOR ACTION

Periodontal regeneration is thought to require the proliferation of st ress-sensitive periodontal ligament (PDL) fibroblast cells. The influe nce of physiological amounts of mechanical stretching on the DNA synth esis potential of human PDL fibroblasts was examined by means of an es tablished, simple in vitro system of stretch application, A significan t increase in the relative levels of incorporation of tritiated thymid ine was observed in cultures stretched for 1-6 h, Neutralising antibod ies for platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) did not blunt the DNA synthesis induction. This mitogenic response to stretch appears to be independent of an autocri ne mechanism involving growth factors in general, because stretch-cond itioned medium, when transferred to non-stretched fibroblasts, did not mimic the mitogenic effect of stretch. (C) 1998 Federation of Europea n Biochemical Societies.