title: Expressions of RANKL/RANK and M-CSF/c-fms in root resorption lacunae in rat molar by heavy orthodontic force.
abstract: The differentiation and functions of osteoclasts are regulated by receptor activator of nuclear factor-κB (RANK)/receptor activator of nuclear factor-κB ligand (RANKL) system that stimulates osteoclasts formation. Macrophage colony-stimulating factor (M-CSF) is also essential for osteoclastogenesis. A recent immunocytochemical study reported that RANKL/RANK and M-CSF/c-fms were localized in the periodontal ligament of rat molars during experimental orthodontic tooth movement. The present study focused on the expressions of RANKL/RANK and M-CSF/c-fms in root resorption area during experimental tooth movement in rats. Forty 6-week-old male Wistar rats were subjected to an orthodontic force of 10 or 50 g with a closed coil spring (wire size: 0.005 inch, diameter: 1/12 inch) ligated to the maxillary first molar cleat by a 0.008 inch stainless steel ligature wire to induce a mesial tipping movement of the upper first molars. Experimental tooth movement was undertaken for 10 days. Each sample was sliced into 6 μm continuous sections in a horizontal direction and prepared for haematoxylin and eosin (H and E) and immunohistochemistry staining for tartrate-resistant acid phosphatase (TRAP), RANK, RANKL M-CSF, and c-fms in root resorption area. Statistical analysis was carried out using a Mann-Whitney U-test with a significance level of P<0.01. On days 7 and 10, immunoreactivity for RANKL/RANK and M-CSF/c-fms was detected in odontoclasts with an orthodontic force of 50 g, but not 10 g. Therefore, RANKL/RANK and M-CSF/c-fms systems may be involved in the process of root resorption by heavy orthodontic force.
authors.affiliation: Department of Orthodontics, Nihon University School of Dentistry at Matsudo, Matsudo, Chiba, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nakano
authors.forename: Masaru
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Shoji
authors.initials: S
authors.lastname: Fujita
authors.forename: Masaki
authors.initials: M
authors.lastname: Asano
authors.forename: Kayo
authors.initials: K
authors.lastname: Saito
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kasai
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D000539:Alveolar Process / Q000473:pathology; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001862:Bone Resorption / Q000473:pathology; D003238:Connective Tissue / Q000473:pathology; D003739:Dental Cementum / Q000473:pathology; D005347:Fibroblasts / Q000473:pathology; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000032:analysis; D016173:Macrophage Colony-Stimulating Factor / Q000032:analysis*; D008297:Male; D008437:Maxilla / Q000473:pathology; D008963:Molar / Q000473:pathology*; D009969:Orthodontic Wires; D010010:Osteoclasts / Q000473:pathology; D010513:Periodontal Ligament / Q000473:pathology; D053245:RANK Ligand / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000032:analysis*; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000032:analysis*; D012391:Root Resorption / Q000473:pathology*; D013314:Stress, Mechanical; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods*
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D016173:Macrophage Colony-Stimulating Factor; D016186:Receptor, Macrophage Colony-Stimulating Factor; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase