title: Migration and Differentiation of GFP-transplanted Bone Marrow-derived Cells into Experimentally Induced Periodontal Polyp in Mice.
abstract: Perforation of floor of the dental pulp is often encountered during root canal treatment in routine clinical practice of dental caries. If perforation were large, granulation tissue would grow to form periodontal polyp. Granulation tissue consists of proliferating cells however their origin is not clear. It was shown that the cells in granulation tissue are mainly from migration of undifferentiated mesenchymal cells of the bone marrow. Hence, this study utilized GFP bone marrow transplantation mouse model. The floor of the pulp chamber in maxillary first molar was perforated using ½ dental round bur. Morphological assessment was carried out by micro CT and microscopy and GFP cell mechanism was further assessed by immunohistochemistry using double fluorescent staining with GFP-S100A4; GFP-Runx2 and GFP-CD31. Results of micro CT revealed alveolar bone resorption and widening of periodontal ligament. Histopathological examination showed proliferation of fibroblasts with some round cells and blood vessels in the granulation tissue. At 2 weeks, the outermost layer of the granulation tissue was lined by squamous cells with distinct intercellular bridges. At 4 weeks, the granulation tissue became larger than the perforation and the outermost layer was lined by relatively typical stratified squamous epithelium. Double immunofluorescent staining of GFP and Runx2 revealed that both proteins were expressed in spindle-shaped cells. Double immunofluorescent staining of GFP and CD31 revealed that both proteins were expressed in vascular endothelial cells in morphologically distinct vessels. The results suggest that fibroblasts, periodontal ligament fibroblasts and blood vessels in granulation tissue were derived from transplanted-bone marrow cells. Thus, essential growth of granulation tissue in periodontal polyp was caused by the migration of undifferentiated mesenchymal cells derived from bone marrow, which differentiated into fibroblasts and later on differentiated into other cells in response to injury.
authors.affiliation: 1. Department of Hard Tissue Research, Matsumoto Dental University Graduate School of Oral Medicine, Shiojiri, Japan; 2. Department of Pediatric Dentistry, Matsumoto Dental University School of Dentistry, Shiojiri, Japan.
authors.forename: Saeka
authors.initials: S
authors.lastname: Matsuda
authors.affiliation: 2. Department of Pediatric Dentistry, Matsumoto Dental University School of Dentistry, Shiojiri, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Shoumura
authors.affiliation: 2. Department of Pediatric Dentistry, Matsumoto Dental University School of Dentistry, Shiojiri, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Osuga
authors.affiliation: 3. Department of Life Science, Faculty of Science, Okayama University of Science, Okayama, Japan.
authors.forename: Hidetsugu
authors.initials: H
authors.lastname: Tsujigiwa
authors.affiliation: 4. Department of Oral Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan; 5. Department of Oral Pathology, Matsumoto Dental University School of Dentistry, Shiojiri, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nakano
authors.affiliation: 1. Department of Hard Tissue Research, Matsumoto Dental University Graduate School of Oral Medicine, Shiojiri, Japan.
authors.forename: Norimasa
authors.initials: N
authors.lastname: Okafuji
authors.affiliation: 1. Department of Hard Tissue Research, Matsumoto Dental University Graduate School of Oral Medicine, Shiojiri, Japan; 5. Department of Oral Pathology, Matsumoto Dental University School of Dentistry, Shiojiri, Japan.
authors.forename: Takanaga
authors.initials: T
authors.lastname: Ochiai
authors.affiliation: 1. Department of Hard Tissue Research, Matsumoto Dental University Graduate School of Oral Medicine, Shiojiri, Japan; 5. Department of Oral Pathology, Matsumoto Dental University School of Dentistry, Shiojiri, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Hasegawa
authors.affiliation: 1. Department of Hard Tissue Research, Matsumoto Dental University Graduate School of Oral Medicine, Shiojiri, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kawakami
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism / Q000473:pathology; D016026:Bone Marrow Transplantation; D002454:Cell Differentiation / Q000235:genetics*; D002465:Cell Movement / Q000235:genetics*; D049109:Cell Proliferation / Q000235:genetics; D003731:Dental Caries / Q000473:pathology / Q000628:therapy*; D003782:Dental Pulp / Q000473:pathology; D003786:Dental Pulp Cavity / Q000254:growth & development / Q000473:pathology; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000166:cytology / Q000637:transplantation; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D051379:Mice; D010514:Periodontal Pocket / Q000473:pathology; D011127:Polyps / Q000473:pathology / Q000628:therapy*
chemical_list: D049452:Green Fluorescent Proteins
keywords: Cell differentiation; Immunohistochemistry; Periodontal ligament; Periodontal polyp