Whole-body vibration can attenuate the deterioration of bone mass and trabecular bone microstructure in rats with spinal cord injury

Abstract

Study design: Experimental, controlled study. Objective: To examine the effects of whole-body vibration (WBV) on bone mass and trabecular bone microstructure (TBMS) during the early stage in juvenile rats with spinal cord injury (SCI). Setting: Studied at the Kio University in Japan. Methods: Thirty-four 8-week-old male Wistar rats were divided into 3 groups: the SCI group, the sham-operation group (SHAM) and the SCI+WBV group. WBV started on the 8th day after SCI. After 1 or 2 weeks of WBV treatment, measurements of tissue mineral density, trabecular bone mineral content (BMC) and parameters of TBMS were obtained by scanning the proximal tibias with x-ray micro-computed tomography. Serum levels of osteocalcin (OC) and of tartrate-resistant acid phosphatase 5b (TRACP 5b) were measured with ELISA. Results: BMC, volume bone mineral density, bone volume (BV), BV fraction (BV/tissue volume) and connectivity density (Conn.D) of TBMS parameters were significantly higher in SCI+WBV rats than in SCI rats after 2-week WBV. The BMC and BV/TV of bone mass index correlated well with Conn.D, suggesting the preservation of Conn.D. induced by WBV. SCI+WBV rats showed a decrease in serum OC after 1-week WBV, but a quick recovery from that after 2-week WBV. There was no difference in serum TRACP 5b among the 3 groups throughout the experimental period. Conclusion: WBV treatment could attenuate the bone deterioration that occurs during the early stage in juvenile rats with SCI. In a clinic, this early WBV intervention may be an effective rehabilitation modality for preventing bone fragility in SCI patients. Spinal Cord (2016) 54, 597-603; doi:10.1038/sc.2015.220; published online 22 December 2015 INTRODUCTION Osteoporosis is a well-known complication of spinal cord injury (SCI).The mechanism of bone loss by SCI is complex and is constituted by multiple factors involving mechanical, neurovascular, hormonal and metabolic factors. 1,2 Bone loss following SCI begins within the first 6 months after the injury, and stabilizes between 12 and 16 months. 3 Bone loss is especially prominent in sublesional bones such as the distal femur and proximal tibia. [4][5][6][7][8] In fact, bone mass in the distal femur and proximal tibia decreased by 51% and 70%, respectively, within 1 year after the injury in SCI patients. 6 These two bones were so fragile that even a weak physical impact could cause a fracture in SCI patients. 7,8 Therefore, the frequency of fracture in SCI patients was about twice as high as that of healthy people. 9 Edwards et al. 10 showed that in the femur and tibia of acute SCI patients trabecular bone mineral content (BMC) was reduced by 3.1-4.4% per month and volumetric bone mineral density (BMD) by 2.7-4.7% per month within 4 months after the injury. In addition, cortical BMC and volumetric BMD were noticeably reduced, and furthermore bone strength indices were decreased. 10 The incidence of SCI is higher in young people aged 15-24 years. 11 Children (aged 5-13 years) with

Vaspin antagonizes high fat-induced bone loss in rats and promotes osteoblastic differentiation in primary rat osteoblasts through Smad-Runx2 signaling pathway

“…Microcomputed tomography (Micro-CT) was performed using a Skyscan 1176 μCT scanner (Bruker, Belgium) with a slight modification from previous reports [24,25]. The left femurs were scanned with the following parameters: scanning accuracy was 17.93 μm, 180°rotating scanning, filter for 1 mm A1, scanning voltage 70kv, current 278 μA, and exposure time 450 ms.…”

Spinal Cord Injury as a Model of Bone-Muscle Interactions: Therapeutic Implications From in vitro and in vivo Studies

“…In 2016, Dudley-Javoroski et al showed that 12 months of vibration training did not preserve BMD or trabecular architecture in subjects affected by chronic SCI, showing bone tissue insensitivity to mechanical loading interventions (63). These results are not in line with the previous studies performed on rats, where WBV seemed to attenuate the bone loss that commonly occurs during the early acute stages after SCI (64). On the other hand, WBV seems to have a positive role in ankle spasticity, balance, and walking ability in patients with incomplete SCI at the cervical level (65), suggesting a potential synergistic role with other therapeutic interventions.…”

Possible effects of whole body vibration on bone properties in growing rats

“…The effects of WBV on bone properties may be influenced by not only the WBV-starting age but also bone condition, i.e., normal health or osteopenia, in young rats. However, WBV was reported to improve bone mass and structure by increasing bone formation or decreasing bone resorption in both normal and osteopenia rodents older than 4 weeks [[13], [14], [15], [16], [17]]. On the other hand, the effects of WBV on bone properties were inconsistent among young rodents under the age of 4 weeks [18,19].…”

“…Analyzes of bone mass and trabecular bone microstructure (TBMS) were performed as previously reported [13]. Using an X-ray micro-computed tomography device (Micro-CT; Hitachi Medical Corp., Tokyo, Japan), the left proximal tibia was scanned at 70 kV, 90 μA, with a voxel size of 19.2 μm in the high-definition mode for TBMS analysis.…”

“…In animal studies, WBV was found to increase bone mass and improve structural parameters in young rodents (aged ≤8 weeks) with spinal cord injury, unloading or ovariectomy [[13], [14], [15]]. On the other hand, a few studies examined the potential effects of WBV on bone mass in normal young rodents [[16], [17], [18]].…”