title: Gene expression analysis of resident macrophages in lipopolysaccharide-stimulated rat molar pulps.
abstract: BACKGROUND
  In normal dental pulp, a considerable number of resident macrophages are distributed. This study was designed to analyze the expression levels of genes associated with differentiation and function of resident macrophages in rat molar pulps stimulated with lipopolysaccharide (LPS).
  
  
  METHODS
  Mandibular first molars of 7-week-old male Wistar rats were used. After transcardiac perfusion with a culture medium to preserve tissue integrity, pulpotomy and LPS application were carried out on the experimental teeth, and then dissected mandibles were subjected to whole-tooth culture for 3 days. Normal teeth and pulpotomized teeth without LPS served as controls. The specimens were then immunostained for ED1 (CD68, a general macrophage marker) and ED2 (CD163, a resident macrophage marker). Real-time polymerase chain reaction for Toll-like receptor 4 (TLR4), CD14, chemokine receptors (CCR2 and CX3CR1), and colony-stimulating factor-1 (CSF1) mRNAs was carried out after laser capture microdissection of ED1+ and ED2+ cells.
  
  
  RESULTS
  LPS-treated pulps showed significant increases in (1) density of ED1+ and ED2+ cells beneath the amputation site and (2) expression levels of TLR4, CD14, CSF1, and CX3CR1 mRNAs, as compared with non-LPS-treated groups. CCR2 mRNA showed no significant difference between each group.
  
  
  CONCLUSIONS
  LPS treatment of cultured rat molars caused the accumulation of resident macrophages and enhanced the expression of TLR4, CD14, CSF1, and CX3CR1 mRNAs in these cells. Up-regulation of these molecules might be involved in the differentiation and subsequent migration of resident macrophages of the pulp.
authors.affiliation: Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Uraiwan
authors.initials: U
authors.lastname: Chokechanachaisakul
authors.forename: Tomoatsu
authors.initials: T
authors.lastname: Kaneko
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamanaka
authors.forename: Reika
authors.initials: R
authors.lastname: Kaneko
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Katsube
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Jacques E
authors.initials: JE
authors.lastname: Nör
authors.forename: Takashi
authors.initials: T
authors.lastname: Okiji
authors.forename: Hideaki
authors.initials: H
authors.lastname: Suda
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D015214:Antigens, Differentiation, Myelomonocytic / Q000276:immunology; D000073883:CX3C Chemokine Receptor 1; D003786:Dental Pulp Cavity / Q000276:immunology* / Q000382:microbiology; D020869:Gene Expression Profiling; D016130:Immunophenotyping; D061346:Laser Capture Microdissection; D008070:Lipopolysaccharides; D008264:Macrophages / Q000276:immunology*; D008297:Male; D008963:Molar; D009924:Organ Culture Techniques; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D054390:Receptors, CCR2 / Q000096:biosynthesis / Q000235:genetics; D011956:Receptors, Cell Surface / Q000276:immunology; D019707:Receptors, Chemokine / Q000096:biosynthesis / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis / Q000235:genetics; D015854:Up-Regulation; D000098902:CD163 Antigen; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000073883:CX3C Chemokine Receptor 1; D008070:Lipopolysaccharides; D054390:Receptors, CCR2; D011956:Receptors, Cell Surface; D019707:Receptors, Chemokine; D051197:Toll-Like Receptor 4; D000098902:CD163 Antigen; C539355:CD68 protein, rat; D000097382:CD68 Molecule; C516305:CX3CR1 protein, rat; C515336:Ccr2 protein, rat