Seven Day Insertion Rest in Whole Body Vibration Improves Multi-Level Bone Quality in Tail Suspension Rats

Abstract

ObjectiveThis study aimed to investigate the effects of low-magnitude, high-frequency vibration with rest days on bone quality at multiple levels.MethodsForty-nine three-month-old male Wistar rats were randomly divided into seven groups, namely, vibrational loading for X day followed by X day rest (VLXR, X = 1, 3, 5, 7), vibrational loading every day (VLNR), tail suspension (SPD), and baseline control (BCL). One week after tail suspension, rats were loaded by vibrational loading (35 Hz, 0.25 g, 15 min/day) except SPD and BCL. Fluorescence markers were used in all rats. Eight weeks later, femora were harvested to investigate macromechanical properties, and micro-computed tomography scanning and fluorescence test were used to evaluate microarchitecture and bone growth rate. Atomic force microscopy analyses and nanoindentation test were used to analyze the nanostructure and mechanical properties of bone material, respectively. Inductively coupled plasma optical emission spectroscopy was used for quantitative chemical analyses.ResultsMicroarchitecture, mineral apposition rate and bone formation rate and macromechanical properties were improved in VL7R. Grain size and roughness were significantly different among all groups. No statistical difference was found for the mechanical properties of the bone material, and the chemical composition of all groups was almost similar.ConclusionsLow-magnitude, high-frequency vibration with rest days altered bone microarchitecture and macro-biomechanical properties, and VL7R was more efficacious in improving bone loss caused by mechanical disuse, which provided theoretical basis and explored the mechanisms of vibration for improving bone quality in clinics.

Low-magnitude mechanical vibration regulates expression of osteogenic proteins in ovariectomized rats

“…To find out the optimal protocol for mechanical stimuli, previous studies have studied the outcomes of vibration with various frequencies, magnitudes and loading cycles. Several recent findings indicated that intermittent vibration with resting periods had significantly enhanced osteogenic effect on bone formation [22,23]. In the present study, we further explored the underpinning mechanism by which mechanic vibration with various resting days regulates the skeletal homeostasis in an ovariectomy-induced rat model of osteoporosis.…”

“…Findings from previous studies including ours indicated that, compared to continuous vibration, intermittent vibration with resting periods improves the biomechanical properties and microstructure of bones in ovariectomized rats [20e22]. A recently published study showed an optimized whole-body vibration regimen in treatment of osteoporosis in rats with tail suspension, which is consisted of repeated low-magnitude and high-frequency vibrations separated by a 7-day resting period for a 8-week treatment course [23]. However, the effects of different vibration regimens on bone anabolics and expression of osteogenesis-related proteins are largely unknown.…”

Administration duration influences the effects of low‐magnitude, high‐frequency vibration on ovariectomized rat bone

“…The effect of long‐term cyclic/discontinuous vibration regimen on osteoporotic bone will be tested in the future. According to the promising results of Zhang et al in tail suspension rats, administration of LMHFV with rest day insertion was more effective in improving bone properties . It is also proven by Sen et al that the mechanical efficacy on the differentiation of MSCs can be enhanced by the incorporation of a refractory period into the loading regimen .…”

Marrow adipogenesis and bone loss that parallels estrogen deficiency is slowed by low-intensity mechanical signals

“…Scientists considering OVX as a model to evaluate countermeasures for osteopenia must take into account the possibility that the rapid rate of bone loss may severely challenge the ability of any given therapy to restore the compromised architecture. Perhaps the outcome of this study would have been different with longer trials [19,28,29], earlier interventions [30,31], or refractory periods [32,33] to augment the responsiveness of the skeleton.…”