Mechanical vibrations reduce the intervertebral disc swelling and muscle atrophy from bed rest

Loss of functional weight bearing, such as experienced during space flight or bedrest, causes detrimental morphological volume changes to the intervertebral disc (IVD) beyond the normal diurnal cycle (10-13%), and muscle. Bed rest (BR) was used to test the hypothesis that, short-duration, low-magnitude, high-frequency mechanical vibrations will attenuate the IVD swelling and intrinsic back muscle atrophy induced by long-term bedrest. Control and experimental subjects underwent BR for up to 90d and were scanned by CT at 0d and 90d, and by MRI at 0d, 60d, 90d and 8d after completion of BR. In addition, experimental subjects received vibrations at 0.3g and 30Hz for 10min/day. Muscle volume was measured by CT scans and IVD volume was measured by MRI scans. During BR, mechanical vibrations abated the IVD swelling at 60d by 150% and 90d by 65%. Eight days after bed rest, the control group showed a plasticity of 9%, while the experimental group showed no residual change (p>0.05). Mechanical vibrations reduced the intrinsic back muscle atrophy from long-term bed rest by 33% (p>0.05). These data demonstrate the rapid deterioration of the musculoskeletal system with BR but present vibrations as a promising nonpharmacologic countermeasure to disc degeneration and muscle atrophy.