Effect of Elf EM Field Frequency on Neurite Outgrowth

Over 200,000 new cases of spinal cord and peripheral nerve injury occur in the United States every year. Methods for enhancing the repair of these injuries are currently sough. Pulsed electromagnetic fields (PEMFs) have been shown to enhance regeneration of central nervous system (CNS) and peripheral nerve tissue both in vitro and in vivo. The mechanism of enhancing regeneration is unknown, but is probably linked to one or more frequency components of the PEMF since "window" effectiveness using certain pulse combinations have been observed. To pinpoint frequency "windows" in the Extremely Low Frequency (ELF) spectrum for peripheral nerve regeneration, chick dorsal root ganglia (DRG) will be exposed to sinusoidal electromagnetic fields from 5 Hz to 355 Hz. DRG will be exposed at both constant current density and constant magnetic field amplitude, and the neurite elongation is measured. A special function generator will be designed to allow flexibility in choosing the increments of frequen- cy to be studied without passing over any "windows". Should a certain frequency prove to substantially increase neurite outgrowth, future studies will be done to prove the frequency's effectiveness in enhancing nerve regeneration in vivo (in peripheral and CNS tissue) and in human subjects.