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

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.