Affiliate Professor University of Washington Seattle, Washington, United States
Introduction:: Electromagnetic stimulation has been successfully used to treat fracture healing and congenital pseudoarthrosis. However, little is known about the mechanisms involved in the influence of electrical stimulation on osteogenesis. Moreover, the effects of different electromagnetic pulse parameters on osteogenesis have not been investigated in detail. Our goal was to study the dose-response behavior of pulsed electromagnetic fields on the skeletal growth of chick embryos.
Materials and Methods:: We designed and fabricated three different tunable electromagnetic pulse generators. These generators were used to supply current to a rectangular coil for generating an electromagnetic field inside an incubator where fertilized chicken eggs were placed in trays. The fertilized eggs were obtained from a hatchery in five batches, each containing 240 eggs. Eggs from each batch were divided equally into test and control groups and incubated in two different incubators. Each test group was then exposed to a different pulsed electromagnetic field. Several embryos from both groups were examined from the 7th day of incubation until the day of hatching, i.e. 21 days. Subsequently, their skeleton was stained in Alizarin red-s. The stained tibiae and femora were dissected under a microscope, and their lengths were measured. These bones were then dried, and their bending strength and mineral content were determined.
Results, Conclusions, and Discussions:: Embryos exposed to a pulse type 1 with a repetition rate of 200/second produced an increased growth rate compared to the control group. However, when the fertilized eggs were exposed to a different electromagnetic pulse, the rate of growth of their long bones was less than those from the control group. The long bones from these test groups also showed decreased weight and mechanical strength compared to the controls. Our results indicated that the growth rate of long bones from chick embryos depended on the type of pulse electromagnetic stimulation. These results show the need for further investigation to determine the parameters for pulse electromagnetic stimulation for optimal clinical application.
