title: Photothermal stress triggered by near-infrared-irradiated carbon nanotubes up-regulates osteogenesis and mineral deposition in tooth-extracted sockets.
abstract: OBJECTIVE
  The bone regenerative healing process is often prolonged, with a high risk of infection particularly in elderly and diseased patients. A reduction in healing process time usually requires mechanical stress devices, chemical cues, or laser/thermal therapies. Although these approaches have been used extensively for the reduction of bone healing time, the exact mechanisms involved in thermal stress-induced bone regeneration remain unclear.
  
  
  METHODS
  Photothermal stress (PTS) stimulation was carried out using a novel photothermal device, composed of an alginate gel (AG) including carbon nanotubes (CNT-AGs) and their irradiator with near-infrared (NIR) light. We investigated the effects of optimal hyperthermia on osteogenesis, its signalling pathway in vitro and mineral deposition in tooth-extracted sockets in vivo.
  
  
  RESULTS
  The PTS (10 min at 42 °C, every day), triggered by NIR-induced CNT, increased the activity of alkaline phosphatase (ALP) in mouse osteoblast MC3T3-E1 cells in a time-dependent manner compared with the non-thermal stress control. PTS significantly induced the expression of osteogenic-related molecules such as ALP, RUNX2 and Osterix in a time-dependent manner with phosphorylated mitogen-activated protein kinases (MAPK). PTS increased the expression of heat shock factor (HSF) 2, but not HSF1, resulting in activation of heat shock protein 27. PTS significantly up-regulated mineral deposition in tooth-extracted sockets in normal and ovariectomised osteoporotic model mice in vivo.
  
  
  CONCLUSIONS
  Our novel CNT-based PTS up-regulated osteogenesis via activation of heat shock-related molecules, resulting in promotion of mineral deposition in enhanced tooth-extracted sockets.
authors.affiliation: a Centre for Regenerative Medicine, Fukuoka Dental College , Fukuoka .|b Department of Physiological Science and Molecular Biology , Fukuoka Dental College , Fukuoka , and.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kajiya
authors.affiliation: a Centre for Regenerative Medicine, Fukuoka Dental College , Fukuoka .
authors.forename: Yuri
authors.initials: Y
authors.lastname: Katsumata
authors.affiliation: b Department of Physiological Science and Molecular Biology , Fukuoka Dental College , Fukuoka , and.
authors.forename: Mina
authors.initials: M
authors.lastname: Sasaki
authors.affiliation: b Department of Physiological Science and Molecular Biology , Fukuoka Dental College , Fukuoka , and.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsutsumi
authors.affiliation: a Centre for Regenerative Medicine, Fukuoka Dental College , Fukuoka .|c Department of Dental Engineering , Fukuoka Dental College , Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Kawaguchi
authors.affiliation: a Centre for Regenerative Medicine, Fukuoka Dental College , Fukuoka .
authors.forename: Tadao
authors.initials: T
authors.lastname: Fukushima
mesh_terms: D000464:Alginates; D000818:Animals; D015519:Bone Density; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D005782:Gels; D020723:Glucuronic Acid; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000235:genetics; D018869:Heat-Shock Response / Q000502:physiology*; D006603:Hexuronic Acids; D006979:Hyperthermia, Induced / Q000009:adverse effects; D008027:Light; D008297:Male; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D037742:Nanotubes, Carbon; D010012:Osteogenesis; D010024:Osteoporosis / Q000378:metabolism; D010052:Ovariectomy; D012333:RNA, Messenger / Q000378:metabolism; D014081:Tooth Extraction; D020390:Tooth Socket / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics
chemical_list: D000464:Alginates; D004268:DNA-Binding Proteins; D005782:Gels; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D006603:Hexuronic Acids; C490017:Hsf1 protein, mouse; C531390:Hsf2 protein, mouse; D037742:Nanotubes, Carbon; D012333:RNA, Messenger; D014157:Transcription Factors; D020723:Glucuronic Acid; D020928:Mitogen-Activated Protein Kinases
keywords: Carbon nanotubes; heat shock proteins; mineral deposition; osteogenesis; photothermal stress