title: Low-magnitude high-frequency vibration (LMHFV) enhances bone remodeling in osteoporotic rat femoral fracture healing.
abstract: Low-magnitude high-frequency vibration (LMHFV) (35 Hz, 0.3 g) accelerates fracture healing by enhancing callus formation and mineralization for both normal and osteoporotic rats in our previous studies.1,2 We hypothesized that LMHFV enhances fracture healing through bone remodeling. Ibandronate was used to suppress LMHFV-stimulated bone remodeling and changes in remodeling were investigated to verify our hypothesis. Closed femoral fractures were created in 80 osteoporotic female Sprague-Dawley rats. The rats were randomly assigned into control (CG), LMHFV (VG) (20 min/day, 5 days/week), ibandronate (BG) (7 µg/kg/week), or LMHFV + ibandronate (VBG) for a treatment duration of 2, 4, 6, or 8 weeks. Blood was taken and the femora were harvested for histological and radiological analyses. VG had the fastest drop in callus area (CA) and width (CW), and bone volume to tissue volume ratio (BV/TV); whereas, a plateaued trend in BG and VBG was observed. The fastest callus reduction, highest mineral apposition rate at week 6, and increased serum concentration of osteocalcin and TRAP5b in VG suggested enhanced remodeling. LMHFV partially reversed the inhibition of bone remodeling by ibandronate suggested LMHFV had an opposite effect on bone remodeling to ibandronate. In conclusion, LMHFV accelerated fracture healing by enhancing bone remodeling and the administration of ibandronate can impair this enhancement. LMHFV has great potential in improving fracture outcome clinically.
authors: Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, 5/F, Clinical Science Building, Shatin, New Territories, Hong Kong SAR, People's Republic of China.
authors: Dick Ho-Kiu
authors: DH
authors: Chow
authors: Kwok-Sui
authors: KS
authors: Leung
authors: Ling
authors: L
authors: Qin
authors: Andraay Hon-Chi
authors: AH
authors: Leung
authors: Wing-Hoi
authors: WH
authors: Cheung
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000187:drug effects / Q000502:physiology*; D002146:Bony Callus / Q000187:drug effects; D004164:Diphosphonates / Q000494:pharmacology; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000628:therapy*; D017102:Fracture Healing / Q000502:physiology*; D000077557:Ibandronic Acid; D015675:Osteocalcin / Q000378:metabolism; D010010:Osteoclasts / Q000187:drug effects / Q000502:physiology; D058866:Osteoporotic Fractures / Q000000981:diagnostic imaging / Q000628:therapy*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014732:Vibration; D055114:X-Ray Microtomography
chemical_list: D004164:Diphosphonates; D015675:Osteocalcin; D000077557:Ibandronic Acid