title: Electromagnetic wave irradiation promotes osteoblastic cell proliferation and up-regulates growth factors via activation of the ERK1/2 and p38 MAPK pathways.
abstract: OBJECTIVE
  Periodontitis with bone resorption is caused by inflammatory reactions to bacterial infection. We recently reported that electromagnetic wave irradiation (EMWI) has bactericidal effects. However, the effects of EMWI on periodontal tissues remain unclear. This study was aimed to investigate the effects of EMWI on osteoblasts.
  
  
  METHODS
  Osteoblastic cells MC3T3-E1 were treated with EMWI (500-1,000 kHz, 5 times, 1 sec/time). Cell growth and cytotoxicity were determined by cell proliferation assays and measurement of lactate dehydrogenase release, respectively. Gene expression and protein production of growth factors were analyzed using real-time PCR and ELISA, respectively. EMWI-activated cellular signal transduction pathways were investigated by immunoblotting and blocking assay with specific inhibitors.
  
  
  RESULTS
  Osteoblasts proliferation was significantly enhanced 3 days after EMWI and no cytotoxicity was observed. EMWI up-regulated various growth factors, such as vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF). EMWI induced ERK1/2, p38 MAPK and SAPK/JNK phosphorylation within 5 min, and the production of PDGF-ΑΑ and VEGF was partially reduced by MAPK-specific inhibitor.
  
  
  CONCLUSIONS
  These findings demonstrated that EMWI increases osteoblastic cell activity and the expression of growth factors via ERK1/2 and p38 MAPK pathways and suggested that EMWI may be beneficial to bone tissue repair such as periodontitis.
authors.affiliation: Department of Conservative Dentistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Yumoto
authors.forename: Kouji
authors.initials: K
authors.lastname: Hirao
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Tominaga
authors.forename: Naoki
authors.initials: N
authors.lastname: Bando
authors.forename: Kanako
authors.initials: K
authors.lastname: Takahashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuo
mesh_terms: D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D049109:Cell Proliferation / Q000528:radiation effects; D060733:Electromagnetic Radiation; D020935:MAP Kinase Signaling System / Q000528:radiation effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D010006:Osteoblasts / Q000166:cytology / Q000528:radiation effects*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000528:radiation effects; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
chemical_list: D010982:Platelet-Derived Growth Factor; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse