Sine wave interaction with an in vivo model of bone development

The effect of various sine waves on the decalcified bone matrix (DBM)-induced endochondral ossification system has been studied. Two groups of ossicle-bearing animals were exposed to sinusoidally time-varying magnetic fields with a peak amplitude of five Gauss and a frequency of 15 Hz (corresponding to a mean electric field of 0.5 mV/m at a radius of 2.1 cm) for 1 and 8 hours, respectively. Two additional groups of animals were exposed to 45-Hz magnetic fields of the same amplitude (giving a mean induced electric field of 1.5 mV/m at a radius of 2.1 cm) and for the same time periods. The developing system is most sensitive to stimulation during the early phases of cell recruitment and chondrogenesis. However, indices of proliferation and cellularity are not increased in any phase of the system, suggesting an effect of electric and magnetic stimulation to increase differentiation or modulate synthesis of extracellular matrix.