Pulsed electromagnetic fields stimulation affects BMD and local factor production of rats with disuse osteoporosis

Abstract

Pulsed electromagnetic fields (PEMF) have been used widely to treat nonunion fractures and related problems in bone healing, as a biological and physical method. With the use of Helmholtz coils and PEMF stimulators to generate uniform time-varying electromagnetic fields, the effects of extremely low frequency electromagnetic fields on bone mineral density (BMD) and local factor production in disuse osteoporosis (DOP) rats were investigated. Eighty 4-month-old female Sprague Dawley (SD) rats were randomly divided into intact (INT) group, DOP group, calcitonin-treated (CT) group, and PEMF stimulation group. The right hindlimbs of all the rats were immobilized by tibia-tail fixation except for those rats in the INT group. Rats in the CT group were injected with calcitonin (2 IU/kg, i.p., once a day) and rats in the PEMF group were irradiated with PEMF immediately postoperative. The BMD, serum transforming growth factor-beta 1 (TGF-beta1), and interleukin-6 (IL-6) concentration of the proximal femur were measured 1, 2, 4, and 8 weeks after treatment. Compared with the CT and DOP groups, the BMD and serum TGF-beta1 concentration in the PEMF group increased significantly after 8 weeks. The IL-6 concentration in the DOP group was elevated significantly after operation. The PEMF group showed significantly lower IL-6 level than the DOP group. The results found demonstrate that PEMF stimulation can efficiently suppress bone mass loss. We, therefore, conclude that PEMF may affect bone remodeling process through promoting TGF-beta1 secretion and inhibiting IL-6 expression.

Effects of pulsed electromagnetic fields on lipid peroxidation and antioxidant levels in blood and liver of diabetic rats

“…PEMF involving a pulse train of 1, 10, 20, 40 Hz, and 1.5 mT in rats with STZ-induced diabetes had no effect on reduced body weight due to STZ but reduced blood glucose levels (14). Assessment of the effects of exposure of rats to 10-Hz square waves (1.8-3.8 mT) or 40 Hz sinusoidal (1.3-2.7 mT) magnetic fields on pancreatic structure and function showed that, after application for 14 days, glucose concentrations decreased in both groups, whereas insulin concentrations increased.…”

Magnetic field strength properties in bone marrow during pulsed electromagnetic stimulation

“…This result suggests that the longer coil-sensor distance, the smaller the geometric difference in PEMF strength, particularly in terms of the uniformity of the stimulated area (i.e., a decrease in focality) at distances >40 mm. Testing the influence of PEMF stimulation on bone tissue in vivo [6,7,11], stimulation conditions with lower spatial focality would be preferable to achieve approximately equal PEMF strength throughout the whole marrow cavity with bone marrow in long bones. To the best of our knowledge, this is the first study investigating PEMF strength based on the measurements in marrow cavity in long bones under 810 stimulation conditions.…”

“…In particular, stimulation intensity depends on stimulator output, distance and position [4,5]. Only a few in vivo studies have shown PEMF effects on bone formation processes in tissue, protein and mRNA levels [6][7][8]. An accompanying problem is the difficulty in determining magnetic field strength inside bone in vivo, as characterization of magnetic field strength in bone during PEMF stimulation under different conditions remains incomplete.…”

Effects of pulsed electromagnetic fields on histomorphometry and osteocalcin in disuse osteoporosis rats

“…Li et al / Effects of pulsed electromagnetic fields on histomorphometry and osteocalcin in DOP rats motion system damage. DOP is frequently seen in hemiplegia, fracture, long-term bed rest, and space flight [1,2]. In recent years, with the increase in the number older individuals and the use of mechanized transportation, the high incidence of disuse osteoporosis is becoming a significant problem in clinical medicine.…”

“…Disuse osteoporosis (DOP) is a kind of secondary osteoporosis that can be caused by various reasons, such as motion ability restriction or dysfunction or 1 These authors contributed equally to this work.…”