title: Mandibular appliance modulates condylar growth through integrins.
abstract: Functional orthopedic therapy corrects growth discrepancies between the maxilla and mandible, possibly through postural changes in the musculature and modulation of the mandibular condylar cartilage growth. Using Wistar rats, we tested the hypothesis that chondrocytes respond to forces generated by a mandibular propulsor appliance by changes in gene expression, and that integrins are important mediators in this response. Immunohistochemical analyses demonstrated that the use of the appliance for different periods of time modulated the expression of fibronectin, alpha5 and alphav integrin subunits, as well as cell proliferation in the cartilage. In vitro, cyclic distension of condylar cartilage-derived cells increased fibronectin mRNA, as well as Insulin-like Growth Factor-I and II mRNA and cell proliferation. A peptide containing the Arginine-Glycine-Asparagine sequence (RGD), the main cell-binding sequence in fibronectin, blocked almost all these effects, confirming that force itself modulates the growth of the rat condylar cartilage, and that RGD-binding integrins participate in mechanotransduction.
authors.affiliation: Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, CEP 05508-000, São Paulo, SP, Brazil.
authors.forename: M Rubia
authors.initials: MR
authors.lastname: Marques
authors.forename: D
authors.initials: D
authors.lastname: Hajjar
authors.forename: K Gomes
authors.initials: KG
authors.lastname: Franchini
authors.forename: A Sigari
authors.initials: AS
authors.lastname: Moriscot
authors.forename: M Fagundes
authors.initials: MF
authors.lastname: Santos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001696:Biomechanical Phenomena; D002356:Cartilage / Q000254:growth & development*; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000502:physiology; D005353:Fibronectins / Q000032:analysis; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007335:Insulin-Like Growth Factor II / Q000032:analysis; D039482:Integrin alpha5 / Q000032:analysis; D039564:Integrin alphaV / Q000032:analysis; D016023:Integrins / Q000502:physiology*; D008297:Male; D008334:Mandible / Q000254:growth & development*; D040542:Mechanotransduction, Cellular / Q000502:physiology; D009842:Oligopeptides / Q000494:pharmacology; D017289:Orthodontic Appliances, Functional; D051381:Rats; D017208:Rats, Wistar; D011971:Receptors, Immunologic / Q000187:drug effects; D013314:Stress, Mechanical
chemical_list: D005353:Fibronectins; D039482:Integrin alpha5; D039564:Integrin alphaV; D016023:Integrins; D009842:Oligopeptides; D011971:Receptors, Immunologic; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; C047981:arginyl-glycyl-aspartic acid