title: Photothermal stress triggered by near infrared-irradiated carbon nanotubes promotes bone deposition in rat calvarial defects.
abstract: 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. In this study, we investigated the effect of optimal hyperthermia on rat calvarial defects in vivo and on osteogenesis in vitro. Photothermal stress stimulation was carried out using a new photothermal device, composed of an alginate gel including in carbon nanotubes and their irradiator with near-infrared light. Photothermal stress (15 min at 42℃, every day), trigged by near-infrared-induced carbon nanotube, promoted bone deposition in critical-sized calvarial defects compared with nonthermal stress controls. We recently reported that our novel DNA/protamine complex scaffold induces bone regeneration in calvarial defects. In this study, photothermal stress upregulated bone deposition in DNA/protamine-engrafted calvarial defects. Furthermore, photothermal stress significantly induced expression of osteogenic related genes in a time-dependent manner, including alkaline phosphatase, osterix, and osteocalcin. This was observed in DNA/protamine cells, which were expanded from regenerated tissue engrafted into the DNA/protamine scaffold, as well as in human MG63 preosteoblasts. In summary, this novel carbon nanotube-based photothermal stress approach upregulated expression of osteogenic-related genes in preosteoblasts, resulting in promotion of mineral deposition for enhanced bone repair.
authors.affiliation: Department of Oral Rehabilitation, Fukuoka Dental College, Fukuoka, Japan Center for Regenerative Medicine, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Yanagi
authors.affiliation: Center for Regenerative Medicine, Fukuoka Dental College, Fukuoka, Japan Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan kajiya@college.fdcnet.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kajiya
authors.affiliation: Center for Regenerative Medicine, Fukuoka Dental College, Fukuoka, Japan Department of Dental Engineering, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Kawaguchi
authors.affiliation: Department of Oral Rehabilitation, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kido
authors.affiliation: Center for Regenerative Medicine, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Tadao
authors.initials: T
authors.lastname: Fukushima
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001861:Bone Regeneration / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D004247:DNA / Q000737:chemistry; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D007259:Infrared Rays / Q000627:therapeutic use; D008297:Male; D008422:Materials Testing; D037742:Nanotubes, Carbon; D010006:Osteoblasts / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics; D011479:Protamines / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012886:Skull / Q000293:injuries* / Q000473:pathology / Q000503:physiopathology; D054457:Tissue Scaffolds / Q000737:chemistry; D015854:Up-Regulation; D055114:X-Ray Microtomography
chemical_list: D001672:Biocompatible Materials; D037742:Nanotubes, Carbon; D011479:Protamines; D004247:DNA
keywords: DNA/protamine scaffold; Photothermal stress stimulation; bone deposition; osteogenesis; preosteoblasts