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Low‐Intensity Pulsed Ultrasound‐Promoted Bone Healing Is Not Entirely Cyclooxgenase 2 Dependent
Author(s) -
Huang Tsang-Hai,
Tang Chih-Hsin,
Chen Hsiun-Ing,
Fu Wen-Mei,
Yang Rong-Sen
Publication year - 2008
Publication title -
journal of ultrasound in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 91
eISSN - 1550-9613
pISSN - 0278-4297
DOI - 10.7863/jum.2008.27.10.1415
Subject(s) - medicine , low intensity pulsed ultrasound , intensity (physics) , ultrasound , radiology , therapeutic ultrasound , optics , physics
Objective. The purpose of this study was to investigate whether low‐intensity pulsed ultrasound (LIPUS) promotes bone healing through the cyclooxgenase 2 (COX‐2) pathway. Methods. Each male Sprague Dawley rat (n = 48 total) in the study underwent bilateral drilled hole injury in the proximal tibiae. Then the animals were randomly assigned to 2 groups: a COX‐2 inhibitor (COX‐2in) group, treated with the selective COX‐2 inhibitor rofecoxib (3 mg/kg/d), and a control (CON) group, treated with distilled water. Low‐intensity pulsed ultrasound was applied to the injured site of a single limb of each rat for 20 min/d at a consistent intensity (30 mW/cm 2 ) and frequency (1.5 MHz). Subsets of animals from both groups were killed after 3, 7, or 14 days of single‐limb LIPUS treatment. Tissue sections were subjected to alcian blue staining, and the healing status was quantified according to a scoring system. Results. After 3 and 7 days, the CON group's LIPUS‐treated limbs had significantly higher healing scores than its nontreated limbs and the COX‐2in group's LIPUS‐treated limbs ( P < .05). Interestingly, after the 14‐day treatment, the COX‐2in group's LIPUS‐treated limbs had significantly higher healing scores than its nontreated limbs ( P < .05) but showed no difference when compared with the CON group. Conclusions. Low‐intensity pulsed ultrasound did show accelerative efficacy on bone healing. Selective inhibition of COX‐2 could delay but not entirely block the benefits of LIPUS on bone healing. Low‐intensity ultrasound treatment could promote bone healing through other, non–COX‐2‐dependent, pathways.