The Short-Term Effects of Difference Frequency of Transcutaneous Electrical Nerve Stimulation on Pain Relief using c-fos Expression in Spinal Cord with Knee Osteoarthritis Rats

PURPOSE: The purpose of this study was to determine the effect of different frequencies (4Hz and 100Hz) of transcutaneous electrical nerve simulation (TENS) on pain relief using c-fos expression in the spinal cord of rat osteoarthritis to investigate the appropriate frequency for pain relief. METHODS: Total of 30 Sprague-Dawley rats was used and randomly divided 2 groups according TENS frequency and applicate the TENS during 3 period (3 days, 7 days, 10 days). The induction of osteoarthritis by 3mg monosodium iodoacetat was injected into the right knee joint of rats. Three days later, commercially available TENS unit was used for stimulation was set to 20minutes on 3, 7, 10 days after surgery. Western blot analysis system was used to detect immunoreactive proteins. The thickness of the bands were photographically measured by Scion Image. RESULTS: When investigating the c-fos expression of TENS on spinal cord in OA knee over 10 days, between-groups differences in c-fos expression reached a significant level by day 10. For within-groups comparisons, the c-fos expression decreased significantly across days in low- and high-frequency TENS groups. CONCLUSION: Whether at low- and high-frequency, the TENS as a therapy obtained beneficial effects of pain relief and TNES at high-frequency is more beneficial effects on the pain relief when TENS applied at injury site.