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Low‐intensity pulsed ultrasound accelerates fracture healing by stimulation of recruitment of both local and circulating osteogenic progenitors
Author(s) -
Kumagai Ken,
Takeuchi Ryohei,
Ishikawa Hiroyuki,
Yamaguchi Yuichiro,
Fujisawa Takahiro,
Kuniya Takashi,
Takagawa Shu,
Muschler George F.,
Saito Tomoyuki
Publication year - 2012
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.22103
Subject(s) - low intensity pulsed ultrasound , bone healing , homing (biology) , progenitor cell , green fluorescent protein , stimulation , stromal cell , femoral fracture , chemistry , alkaline phosphatase , hindlimb , andrology , medicine , stem cell , anatomy , surgery , ultrasound , femur , biology , microbiology and biotechnology , therapeutic ultrasound , ecology , biochemistry , radiology , gene , enzyme
We investigated the effect of low‐intensity pulsed ultrasound (LIPUS) on the homing of circulating osteogenic progenitors to the fracture site. Parabiotic animals were formed by surgically conjoining a green fluorescent protein (GFP) mouse and a syngeneic wild‐type mouse. A transverse femoral fracture was made in the contralateral hind limb of the wild‐type partner. The fracture site was exposed to daily LIPUS in the treatment group. Animals without LIPUS treatment served as the control group. Radiological assessment showed that the hard callus area was significantly greater in the LIPUS group than in the control group at 2 and 4 weeks post‐fracture. Histomorphometric analysis at the fracture site showed a significant increase of GFP cells in the LIPUS group after 2 weeks (7.5%), compared to the control group (2.4%) ( p < 0.05). The LIPUS group exhibited a significantly higher percentage of GFP cells expressing alkaline phosphatase (GFP/AP) than the control group at 2 weeks post‐fracture (5.9%, 0.3%, respectively, p < 0.05). There was no significant difference in the percentage of GFP/AP cells between the LIPUS group (2.0%) and the control group (1.4%) at 4 weeks post‐fracture. Stromal cell derived factor‐1 and CXCR4 were immunohistochemically identified at the fracture site in the LIPUS group. These data indicate that LIPUS induced the homing of circulating osteogenic progenitors to the fracture site for possible contribution to new bone formation. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1516–1521, 2012