title: Three-dimensional loading model for periodontal ligament regeneration in vitro.
abstract: In this study we present a new three-dimensional (3D) model to study effects of mechanical loading on tendon/ligament formation in vitro. The model mimics a functional periodontal ligament (PDL), which anchors dental roots to the jaw bone and transfers the axial load of mastication to the jaw bone. A collagen gel containing human PDL fibroblasts was seeded in a PDL space between an artificial root and bone surface. The effects of 3-day loading on the fibroblasts were studied in vitro by axial and intermittent displacement of the root to which the gel was attached. Cell responses were recorded by measuring expression of three sets of genes: (i) cyclooxygenase 1 and 2 (COX-1, COX-2) producing prostaglandins (signaling molecules); (ii) Runx2, a transcription factor for the osteogenic lineage; and (iii) the extracellular matrix proteins osteopontin, dentin matrix protein 1, and collagen type I (COL1). Loading for 3 days resulted in magnitude-dependent changes in the expression of COX-2 and COL1. A low loading magnitude significantly decreased COX-2 expression, an intermediate magnitude increased its expression, while a high magnitude increased COL1 expression. We concluded that the 3D loading model provides a useful, well-controlled method to examine ligament fibroblast responses to mechanical loading. The model may serve to explore the application of mechanical loading as an anabolic factor for ligament reconstruction.
authors.affiliation: Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam , Amsterdam, The Netherlands .
authors.forename: Agnes D
authors.initials: AD
authors.lastname: Berendsen
authors.forename: Theo H
authors.initials: TH
authors.lastname: Smit
authors.forename: X Frank
authors.initials: XF
authors.lastname: Walboomers
authors.forename: Vincent
authors.initials: V
authors.lastname: Everts
authors.forename: John A
authors.initials: JA
authors.lastname: Jansen
authors.forename: Antonius L J J
authors.initials: AL
authors.lastname: Bronckers
mesh_terms: D000328:Adult; D001577:Benzophenones; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005782:Gels; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007659:Ketones / Q000494:pharmacology; D008297:Male; D008954:Models, Biological; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D011092:Polyethylene Glycols / Q000494:pharmacology; D011108:Polymers; D011392:Proline / Q000378:metabolism; D012038:Regeneration / Q000187:drug effects / Q000502:physiology*; D023822:Tissue Engineering; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult
chemical_list: D001577:Benzophenones; D024042:Collagen Type I; D005782:Gels; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D011392:Proline; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human