title: Optimal compressive force accelerates osteoclastogenesis in RAW264.7 cells.
abstract: Mechanical stress produced by orthodontic forces is a factor in the remodeling of periodontal ligaments (PDLs) and alveolar bone. It has been reported that the expression of a number of cytokines associated with osteoclastogenesis is upregulated when compressive forces act on osteoblasts and PDL cells. The present study investigated the effects of compressive forces on the formation of osteoclasts from the macrophage cell line RAW264.7. Compressive forces on osteoclasts were exerted using layers of 3, 5, 7, 9 or 14 glass cover slips on the 4th day of culture for 24 h. The number of osteoclasts was determined by counting the number of cells positive for tartrate-resistant acid phosphatase staining. Osteoclastogenesis advanced rapidly on days four and five. The number of osteoclasts with >8 nuclei peaked when the force of 7 slips was applied, which was therefore regarded as the optimal compressive force. Alterations in the expression of osteoclast-associated genes are associated with changes in the differentiation and fusion of macrophages in response to compressive forces; therefore, osteoclast-associated genes were assessed by reverse transcription quantitative polymerase chain reaction in the present study. The mRNA expression of osteoclast‑associated genes increased significantly after 3 h of optimal compression, whereas mRNA expression increased after 24 h in the control group. These findings suggested that osteoclastogenesis of macrophages was accelerated when an optimal compressive force was applied.
authors.affiliation: Department of Orthodontics, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060‑8586, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Hayakawa
authors.affiliation: Department of Molecular Cell Pharmacology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060‑8586, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Yoshimura
authors.affiliation: Department of Pediatric Dentistry, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060‑8586, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kikuiri
authors.affiliation: Department of Molecular Cell Pharmacology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060‑8586, Japan.
authors.forename: Mino
authors.initials: M
authors.lastname: Matsuno
authors.affiliation: Department of Pediatric Dentistry, Faculty of Dentistry, Tokushima University, Tokushima 770‑8504, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Hasegawa
authors.affiliation: Department of Orthodontics, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060‑8586, Japan.
authors.forename: Kumu
authors.initials: K
authors.lastname: Fukushima
authors.affiliation: Department of Orthodontics, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060‑8586, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Shibata
authors.affiliation: Department of Molecular Cell Pharmacology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060‑8586, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Deyama
authors.affiliation: Department of Molecular Cell Pharmacology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060‑8586, Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Orthodontics, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060‑8586, Japan.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Iida
mesh_terms: D000818:Animals; D001862:Bone Resorption; D018929:Cell Culture Techniques; D002460:Cell Line; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D051379:Mice; D010010:Osteoclasts / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D013314:Stress, Mechanical
chemical_list: D012333:RNA, Messenger