Effects of Electrical Stimulus on Bone Properties in Rats with Sciatic Denervation

Abstract

: This study investigated the effects of electrical stimulus on bone properties in rats with sciatic denervation. Forty-eight Wistar rats aged 8 week-old were used and divided into 4 groups, randomly. One group was sham-operated SHAM as a control, and the sciatic nerves of the lateral hind limbs were cut in the remaining 3 groups DN . Two groups of DN rats received electrical stimulus at both hind limbs to induce planter flexion for 15 min, 2 sets day, 5 days week, at 15 or 60 Hz. The rats in each group were sacrificed at 1, 2, 3 and 4 weeks after the operation. All tibias were measured by three-pointed bending test, and bone mechanical strength was calculated. Also, the dry bone weight and ash content of the bones were measured. A reduction of all bone properties in DN was shown from a week after operation onwards and that in DN 15 Hz from two weeks after operation onwards. Bone properties in DN 60 Hz were decreased in order of maximum load, ash content, mechanical strength, and dry bone weight from two weeks after operation onwards. These results suggest that electrical stimulus can delay the progression of bone atrophy, and that high frequency stimulation 60 Hz is more effective than low frequency stimulation 15 Hz in this regard. Jpn J Rehabil Med 2008 807 813