Castrated male Sprague Dawley rats were subjected to various
capacitively coupled electrical fields for six and eight weeks at two and
4.5 months after castration, respectively, with pairs of electrodes that
were located paraspinally on the surface of the skin dorsally at the
eleventh thoracic and fourth lumbar levels. When the animals were killed,
dry and ash weights per unit of volume (apparent density), elastic modulus,
ultimate stress, work to failure, trabecular area fraction, and mean
trabecular width were determined for selected vertebrae. The results
indicated that a sixty-kilohertz, 100-microampere signal (a calculated
current density of five microamperes root-mean-square per square centimeter
and a field of twelve millivolts root-mean-square per centimeter)
significantly reversed the castration-induced osteoporosis in the lumbar
vertebrae and restored bone mass per unit of volume in rats that had been
stimulated for eight weeks after castration.