Effects of repetitive high frequency transcutaneous electrical nerve stimulation (HF-TENS) on spasticity and motor function following spinal cord injury in rats

[Purpose] The aim of this study was to determine whether high frequency transcutaneous electrical nerve stimulation (HF-TENS) influences spasticity and motor function recovery after spinal cord injury (SCI). [Subjects] Thirty six male Sprague-Dawley rats (200-250 g) were received contusive SCI at T10 level. One week after SCI, 20 rats with SCI showed increased spasticity. Rats with spasticity after SCI were randomly assigned into two groups: the HF-TENS group (n=10) and the control group (n=10). [Methods] HF-TENS stimulation (100 Hz, 200 μs) was applied to anterior tubercle of the tibia near the knee joint and ankle joint in front of the achilles tendon. To test the effects of HF-TENS on spasticity and motor function recovery, we assessed BBB, combined behavioral score and Modified Ashworth scale for 9 days, at 1 hour after HF-TENS application on hindlimb. [Results] Rats with HF-TENS showed a significant decrease in spasticity 7 days after the HF-TENS application and a prominent improvement in functional outcome 5 days after the HF-TENS application compared to the control group. [Conclusion] Our results suggest that HF-TENS may help relieve spasticity and improve recovery of motor function after SCI.