The Correlation Between Dielectric Properties and Microstructure of Femoral Bone in Rats with Different Bone Qualities

Bone dielectric properties (DP) have been extensively studied. However, little literature has reported DP of bone from identical anatomical site under different status and its correlation with microstructure. Therefore, interrelationship between DP and microstructure of rat femurs with varying bone qualities (normal, osteoporotic and partially osteoporotic) was investigated. Diabetic osteoporosis was induced by streptozotocin (STZ) injection. 8 normal rats as control group together with 16 diabetic rats equally assigned to diabetes mellitus (DM) and DM treated by pulsed electromagnetic fields (PEMF) (DM + PEMF) group were used. DM + PEMF group was daily exposed to PEMF of 15 Hz, 1 mT for 8 weeks. After sacrifice, the femurs were harvested for microCT analysis and dielectric measurements (from 10 Hz to 1 MHz). It was found that DP (conductivity and permittivity) altered after PEMF stimulation improved femoral microstructures ( p < 0.01). Significant correlations were found between microstructure indices (MI) and conductivity in the full frequency range (| r | ≥ 0.64, n = 24) as well as permittivity in middle and low frequencies (| r | ≥ 0.52, n = 24, from 1 Hz to 1 kHz). The findings demonstrated the good correlation between DP and MI of femoral bone in rats, which makes it possible to distinguish bone under different status and predict MI variation through dielectric measurements.