title: Orthodontic tooth movement causes decreased promoter expression of collagen type 1, bone sialoprotein and alpha-smooth muscle actin in the periodontal ligament.
abstract: OBJECTIVE
  To evaluate the effects of orthodontic tooth movement on the promoter expression of collagen type 1 (3.6Col1), bone sialoprotein (BSP) and alpha-smooth muscle actin (αSMA) in the periodontal ligament (PDL) using transgenic mice containing transgenes of these promoters fused to green fluorescent proteins (GFP).
  
  
  METHODS
  The maxillary first molars of 10-12 week-old transgenic mice were loaded with 10-12 g of force for 12, 48 h, or 7 days. Mice were transgenic for one of the following GFP-tagged bone markers of osteoblast lineage cells: 3.6-kb fragment of the rat collagen type 1 promoter (3.6Col1), BSP or α-smooth muscle actin (αSMA). Loaded molars under compression and tension were compared with contra-lateral unloaded controls.
  
  
  RESULTS
  On the compression side of the PDL, orthodontic tooth movement caused a significant decrease in GFP expression of all the promoters at each time point. On the tension side, there was a significant increase in BSP-GFP expression, 12 h following loading compared to the contralateral unloaded controls.
  
  
  CONCLUSIONS
  An in vivo tooth movement model using transgenic mice with promoter-GFP constructs provides an efficient and effective way of investigating the cellular events underlying orthodontic tooth movement. PDL cells may undergo decreased differentiation in response to the compressive force.
authors.forename: C
authors.initials: C
authors.lastname: Olson
authors.forename: F
authors.initials: F
authors.lastname: Uribe
authors.forename: Z
authors.initials: Z
authors.lastname: Kalajzic
authors.forename: A
authors.initials: A
authors.lastname: Utreja
authors.forename: R
authors.initials: R
authors.lastname: Nanda
authors.forename: D
authors.initials: D
authors.lastname: Rowe
authors.forename: S
authors.initials: S
authors.lastname: Wadhwa
mesh_terms: D000199:Actins / Q000032:analysis / Q000235:genetics*; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage; D024042:Collagen Type I / Q000032:analysis / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D049452:Green Fluorescent Proteins; D058574:Integrin-Binding Sialoprotein / Q000032:analysis / Q000235:genetics*; D049408:Luminescent Agents; D008437:Maxilla / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D008963:Molar / Q000473:pathology; D010006:Osteoblasts / Q000473:pathology; D010513:Periodontal Ligament / Q000378:metabolism* / Q000473:pathology; D011401:Promoter Regions, Genetic / Q000235:genetics*; D051381:Rats; D013314:Stress, Mechanical; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000295:instrumentation; D014092:Tooth Root / Q000473:pathology; D019076:Transgenes / Q000235:genetics
chemical_list: D000199:Actins; D024042:Collagen Type I; D058574:Integrin-Binding Sialoprotein; D049408:Luminescent Agents; C544013:alpha-smooth muscle actin, mouse; D049452:Green Fluorescent Proteins