Enhancement of the adolescent murine musculoskeletal system using low-level mechanical vibrations

Dept. of Biomedical Engineering, Psychology A, 3rd Floor, State Univ. of New York at Stony Brook, Stony Brook, NY 11794-2580, USA.
Journal of Applied Physiology (Impact Factor: 3.43). 04/2008; 104(4):1056-62. DOI: 10.1152/japplphysiol.00764.2007
Source: PubMed

ABSTRACT Mechanical signals are recognized as anabolic to both bone and muscle, but the specific parameters that are critical to this stimulus remain unknown. Here we examined the potential of extremely low-magnitude, high-frequency mechanical stimuli to enhance the quality of the adolescent musculoskeletal system. Eight-week-old female BALB/cByJ mice were divided into three groups: baseline controls (BC, n = 8), age-matched controls (AC, n = 12), and whole body vibration (WBV, n = 12) at 45 Hz (0.3 g) for 15 min/day. Following 6 wk of WBV, bone mineralizing surfaces of trabeculae in the proximal metaphysis of the tibia were 75% greater (P < 0.05) than AC, while osteoclast activity was not significantly different. The tibial metaphysis of WBV mice had 14% greater trabecular bone volume (P < 0.05) than AC, while periosteal bone area, bone marrow area, cortical bone area, and the moments of inertia of this region were all significantly greater (up to 29%, P < 0.05). The soleus muscle also realized gains by WBV, with total cross-sectional area as well as type I and type II fiber area as much as 29% greater (P < 0.05) in mice that received the vibratory mechanical stimulus. The small magnitude and brief application of the noninvasive intervention emphasize that the mechanosensitive elements of the musculoskeletal system are not necessarily dependent on strenuous, long-term activity to initiate a structurally relevant response in the adolescent musculoskeletal system. If maintained into adulthood, the beneficial structural changes in trabecular bone, cortical bone, and muscle may serve to decrease the incidence of osteoporotic fractures and sarcopenia later in life.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Fracture healing is impaired in aged and osteoporotic individuals. Because adequate mechanical stimuli are able to increase bone formation, one therapeutical approach to treat poorly healing fractures could be the application of whole body vibration, including low-magnitude high-frequency vibration (LMHFV). We investigated the effects of LMHFV on fracture healing in aged, osteoporotic mice. Female C57BL/6NCrl mice (n = 97) were either ovariectomised (OVX) or sham operated (non-OVX) aged 41 weeks. When aged 49 weeks, all mice received a femur osteotomy stabilised using an external fixator. The mice received whole-body vibrations (20 min/day) with 0.3 g peak-to-peak acceleration and a frequency of 45 Hz. After 10 and 21 days, the osteotomised femurs and intact bones (contra-lateral femurs, lumbar spine) were evaluated using bending-testing, μ-computed tomography (μCT), histology, and gene expression analyses. LMHFV disturbed fracture healing in aged non-OVX mice, with significantly reduced flexural rigidity (-81%) and bone formation (-80%) in the callus. Gene expression analyses demonstrated increased ERβ and Sost expression in the callus of the vibrated animals, but decreased β-catenin, suggesting that ERβ may mediate the negative effects through inhibition of osteoanabolic Wnt/β-catenin signalling. In contrast, in OVX mice LMHFV significantly improved callus properties, with increased flexural rigidity (+1398%) and bone formation (+637%), which could be abolished by subcutaneous oestrogen application (0.025 mg oestrogen/90 day-release pellet). On a molecular level, we found an up-regulation of ERα in the callus of the vibrated OVX mice, whereas ERβ was unaffected, indicating that ERα may mediate the osteoanabolic response. Our results indicate a major role for oestrogen in the mechanostimulation of fracture healing and imply that LMHFV may only be safe and effective in confined target populations.
    Disease Models and Mechanisms 11/2014; 8(1). DOI:10.1242/dmm.018622 · 5.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Variables defining vibration-based biomechanical treatments were tested by their ability to affect the musculoskeleton in the growing mouse. Duration of a vibration bout, but not variations in vibration intensity or number of vibration bouts per day, was identified as modulator of trabecular bone formation rates. Low-intensity vibrations (LIV) may enhance musculoskeletal properties, but little is known regarding the role that individual LIV variables play. We determined whether acceleration magnitude and/or the number and duration of daily loading bouts may modulate LIV efficacy. LIV was applied to 8-week-old mice at either 0.3 g or 0.6 g for three weeks; the number of daily bouts was one, two, or four, and the duration of a single bout was 15, 30, or 60 min. A frequency of 45 Hz was used throughout. LIV induced tibial cortical surface strains in 4-month-old mice of approximately 10 με at 0.3 g and 30 με at 0.6 g. In trabecular bone of the proximal tibial metaphysis, all single daily bout signal combinations with the exception of a single 15 min daily bout at 0.3 g (i.e., single bouts of 30 and 60 min at 0.3 g and 15 and 30 min at 0.6 g) produced greater bone formation rates (BFR/BS) than in controls. Across all signal combinations, 30 and 60 min bouts were significantly more effective than 15 min bouts in raising BFR/BS above control levels. Increasing the number of daily bouts or partitioning a single daily bout into several shorter bouts did not potentiate efficacy and in some instances led to BFR/BS that was not significantly different from those in controls. Bone chemical and muscle properties were similar across all groups. These data may provide a basis towards optimization of LIV efficacy and indicate that in the growing mouse skeleton, increasing bout duration from 15 to 30 or 60 min positively influences BFR/BS.
    Osteoporosis International 01/2015; 26(4). DOI:10.1007/s00198-014-3018-5 · 4.17 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose of review The musculoskeletal system is largely regulated through dynamic physical activity and is compromised by cessation of physical loading. There is a need to recreate the anabolic effects of loading on the musculoskeletal system, especially in frail individuals who cannot exercise. Vibration therapy is designed to be a nonpharmacological analogue of physical activity, with an intention to promote bone and muscle strength. Recent findings Animal and human studies suggest that high-frequency, low-magnitude vibration therapy improves bone strength by increasing bone formation and decreasing bone resorption. There is also evidence that vibration therapy is useful in treating sarcopenia, which confounds skeletal fragility and fall risk in aging. Enhancement of skeletal and muscle strength involves regulating the differentiation of mesenchymal stem cells to build these tissues; mesenchymal stem cell lineage allocation is positively promoted by vibration signals. Summary Vibration therapy may be useful as a primary treatment as well as an adjunct to both physical and pharmacological treatments, but future studies must pay close attention to compliance and dosing patterns, and importantly, the vibration signal, be it low-intensity vibration (< 1g) appropriate for treatment of frail individuals or high-intensity vibration (> 1g) marketed as a training exercise.
    Current Opinion in Endocrinology Diabetes and Obesity 12/2014; 21(6):447-53. DOI:10.1097/MED.0000000000000111 · 3.77 Impact Factor

Full-text (2 Sources)

Available from
Jun 2, 2014