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

Abstract

Low-magnitude, high-frequency vibration (LMHFV) has been proposed as a non-drug anti-osteoporosis treatment. However, the influence of administration duration on its effect is seldom investigated. In this study, the effect of 16-week LMHFV (0.3 g, 30 Hz, 20 min/day) on the bone mineral densities (BMDs), bone mechanical properties, and cellular responses of osteoporotic and healthy rats was examined by in vivo peripheral quantitative computed tomography (pQCT), fracture tests, cell assays, and mRNA quantification. Forty-eight adult rats were equally assigned to sham surgery (SHM), sham surgery with LMHFV (SHMþV), ovariectomy (OVX), and ovariectomy with LMHFV (OVXþV) groups. At week 8, LMHFV ameliorated ovariectomy-induced deterioration of trabecular bone, with a significantly higher tibia trabecular BMD (þ11.2%) being noted in OVXþV rats (vs. OVX). However, this positive effect was not observed at later time points. Furthermore, 16 weeks of LMHFV caused significant reductions in the vertebral mean BMD (À13.0%), trabecular BMD (À15.7%), and maximum load (À21.5%) in OVXþV rats (vs. OVX). Osteoblasts derived from osteoporotic rat bone explants showed elevated BSP and OSX mRNA expression induced by LMHFV on day 1. However, no further positive effect on osteoblastic mRNA expression, alkaline phosphatase activity, or calcium deposition was observed with prolonged culture time. A higher ratio of RANKL/OPG induced by LMHFV suggests that osteoclastogenesis may be activated. Together, these results demonstrate that administration duration played an important role in the effect of LMHFV. Early exposure to LMHFV can positively modulate osteoporotic bone and osteoblasts; however, the beneficial effect seems not to persist over time. Osteoporotic fracture is a significant cause of morbidity and mortality in the elderly.1 As a mechanosensitive tissue, bone adapts its mass, microstructure, and strength in response to dynamic mechanical loading. Hence, people with osteoporosis are encouraged to exercise their musculoskeletal system, as bone mineral density (BMD) can be improved by moderate-to-high-intensity weight-bearing physical activity.2,3 However, few elderly individuals are able to undertake these exercises. One possible alternative modality is low-magnitude, high-frequency vibration (LMHFV), which is performed in a low-impact manner with the possibility of producing results similar to those of physical exercises.4,5 A precursory study in 2001 reported the powerful osteogenic potential of LMHFV, in which the hind limbs of ovine were subjected to mechanical vibration (30 Hz, 0.3 g) resulting in a 34% higher trabecular bone density in the proximal femur compared with that in the control.6 LMHFV has been proposed as a non-pharmacological approach for the prevention and treatment of osteoporosis in elderly postmenopausal women. 7-9Scientific research with respect to LMHFV has been prolific in the past decade. However, initial attempts to stimulate osteoporotic bone formation using this approach have not been uniformly...

Therapeutic effect of localized vibration on alveolar bone of osteoporotic rats

“…In our study, ovariectomized rats had increased food intake and body weight, which is consistent with previous reports [58, 59]. It has been shown that application of whole- body vibration partly restores body weight in ovariectomized animals [60, 61].…”

Intermittent low-magnitude high-frequency vibration promotes osteogenic protein expression and inhibits osteoclastogenic cytokine secretion in osteoblasts

“…Moreover, we found that 0.5 h of iLMHFV can provide optimal results, with longer treatment being less effective. These results were in agreement with previous findings that early exposure to LMHFV can positively modulate osteoporotic bone and osteoblasts; however, the beneficial effects seem to not give a consistent performance over time [39]. We believe that this is because prolonged intermittent vibration could result in similar effect as Intermittent low-magnitude high-frequency vibration promotes osteogenic protein expression and inhibits osteoclastogenic cytokine secretion in osteoblasts sostenuto vibration, which may cause fatigue of cells to mechanical stimuli, leading to desensitization over time.…”

Applying vibration in early postmenopausal osteoporosis promotes osteogenic differentiation of bone marrow-derived mesenchymal stem cells and suppresses postmenopausal osteoporosis progression

“…Li et al [25] found that vibration of 0.25× g , 35 Hz, and 15 min/day for 8 weeks can up-regulate the expression of osteogenesis-related proteins in bone tissues of OVX rats. Qing et al [26] detected that after 8 weeks of vibration at 0.3× g , 30 Hz, and 20 min/day, the deterioration of trabecular bone in OVX rats was ameliorated and the tibia trabecular BMD was significantly increased. However, Brouwers et al [27] used a vibration of 0.3× g , 90 Hz on ovariectomized rats, twice a day for 20 min, 5 days a week for 6 weeks; no changes in structure and strength of tibiae were observed, and the bone structure in rats was still degraded.…”