HUMAN PERIODONTAL-LIGAMENT FIBROBLAST RESPONSE TO PDGF-BB AND IGF-1 APPLICATION ON TETRACYCLINE HCL CONDITIONED ROOT SURFACES

The purpose of this study was to investigate the effect of 2 growth fa ctors, platelet-derived growth factor-BE (PDGF-BB) and insulin-like gr owth factor-1 (IGF-1), alone or in combination, on the adherence of hu man periodontal ligament fibroblast (PDL) to tetracycline HCl (TTC) co nditioned and non-conditioned periodontally involved root surfaces. Th ere were 80 root dentine chips from 80 patients, ranging from 35 to 70 years of age, each with one periodontally involved tooth requiring ex traction. A root dentine chip was obtained from the subgingival surfac e opposite to the periodontal pocket of each extracted tooth. The dent ine chips were randomly distributed into one of 8 groups. In group 1, PDL fibroblasts were cultured and allowed to attach on the dentine sur face. In group 2, PDL fibroblasts were cultured on a PDGF-BB pre-treat ed dentine surface and in group 3, they were cultured on a IGF-1 pre-t reated dentine surface. In group 4, PDL fibroblasts were cultured on a dentine surface pretreated with a combination of PDGF-BB and IGF-1. I n group 5, PDL fibroblasts were cultured and allowed to attach on the TTC conditioned dentine surfaces. In groups 6 and 7, surface of dentin e chips were conditioned with TTC and then were treated with PDGF-BB o r IGF-1 respectively, followed by placement of PDL fibroblast and cult ured. In group 8, dentine surfaces were conditioned with TTC and then pre-treated with a combination of PDGF-BB and IGF-1 before the fibrobl asts were cultured. After 24 h of incubation, the media was removed an d samples were fixed and processed for SEM at magnifications of x34, x 750, x2000. Photographing and evaluation of samples was performed at x 750 in which fibroblast adherence was measured by counting cells withi n a standard test area. The results of the non-TTC conditioned root su rfaces demonstrated a significant increase in fibroblasts adherence in the PDGF-BB and combination PDGF-BB/IGF-1 treatment groups (groups 2, 4) when compared to the control (group 1) as well as the TTC control (group 5). The combination of PDGF-BB/IGF-1 (group 4) did not signific antly improve the adhesion of cells compared to PDGF-BB alone (group 2 ), but did significantly improve adhesion when compared to IGF-1 alone (group 3). There were no significant differences in cell morphology b etween the growth factor groups (groups 2, 3, 4) and control (group 1) . In general, the cells demonstrated a flat, stellate-shaped morpholog y. The results of the TTC conditioned root surfaces, showed a statisti cally significant increase of cellular adherence in the PDGF-BB group (group 6) when compared to the TTC control (group 5), similar to the n on-TTC group (group 2). However, the morphology of the cells in groups 5, 6, 7, and 8 demonstrated generally a rounded or oval shape with on ly an occasional cell exhibiting a flat form. In the experimental syst em of this study, the inclusion of PDGF-BB on the surface of dentine c hips increased the number of adhering PDL cells, and the addition of T TC conditioning had little effect except to change the morphology of a dhering cells.