RRC ID 41789
Author Naruse K, Miyauchi A, Itoman M, Mikuni-Takagaki Y.
Title Distinct anabolic response of osteoblast to low-intensity pulsed ultrasound.
Journal J Bone Miner Res
Abstract Low-intensity pulsed ultrasound, a form of mechanical energy transmitted as high-frequency acoustical pressure waves, provides noninvasive therapeutic treatment for accelerating fracture repair and distraction osteogenesis. Relatively young osteoblasts respond to ultrasound by transiently upregulating message levels of immediate-early genes as well as that of osteocalcin and insulin-like growth factor I (IGF-I). Osteocytes derived from newborn rat tibia and calvaria responded to a lesser extent only in c-fos and cyclooxygenase-2 (COX-2) messages. Compared with the stretched osteocytes, which use stretch-activated and parathyroid hormone (PTH)-potentiated Ca2+ influx as an entry route to the protein kinase A (PKA) signal transduction pathways, there was no evidence of Ca2+ internalization by any of the cells tested on exposure to the ultrasound. On the other hand, inhibitors of p38 mitogen-activated protein kinase (MAPK) and upstream phosphoinositide 3-kinase (PI3K) blocked COX-2 and osteocalcin upregulation by the ultrasound-exposed ST2, murine bone marrow-derived cells. This is distinct from the aforementioned osteocytic response to low-frequency stretching and implies the involvement of integrins. Our findings suggested that accelerated fracture repair and distraction osteogenesis by the low-intensity pulsed ultrasound depend, at least in part, on the stimulation of osteoblastic cells at relatively early stages of osteogenic lineage. Bone is under control of multiple regulatory mechanisms so that diverse physical forces can be reflected to the microenvironment of each cell, in turn, to the entire bone.
Volume 18(2)
Pages 360-9
Published 2003-2-1
DOI 10.1359/jbmr.2003.18.2.360
PMID 12568414
MeSH Animals Animals, Newborn Antineoplastic Agents, Hormonal / pharmacology Blotting, Western Bone Marrow Cells / cytology Bone Marrow Cells / metabolism Bone and Bones / metabolism Bone and Bones / pathology Calcium / metabolism Cell Differentiation Cell Lineage Cyclic AMP-Dependent Protein Kinases / metabolism Cyclooxygenase 2 Dexamethasone / pharmacology Dinoprostone / metabolism Insulin-Like Growth Factor I / metabolism Isoenzymes / metabolism Mice Mitogen-Activated Protein Kinases / antagonists & inhibitors Mitogen-Activated Protein Kinases / metabolism Osteoblasts / diagnostic imaging* Osteoblasts / metabolism Osteoblasts / pathology* Osteocalcin / metabolism Osteocytes / diagnostic imaging Osteocytes / metabolism Osteocytes / pathology Phosphatidylinositol 3-Kinases / metabolism Prostaglandin-Endoperoxide Synthases / metabolism Proto-Oncogene Proteins c-fos / metabolism Rats Reverse Transcriptase Polymerase Chain Reaction Signal Transduction Skull / metabolism Tibia / metabolism Time Factors Ultrasonics* Ultrasonography Up-Regulation p38 Mitogen-Activated Protein Kinases
IF 5.711
Times Cited 115
Human and Animal Cells