A Single Trial of Transcutaneous Electrical Nerve Stimulation Reduces Chronic Neuropathic Pain Following Median Nerve Injury in Rats

Abstract

Neuropathic pain is a devastating chronic condition and is often induced in the upper limb following nerve injury or damage. Various drugs or surgical methods have been used to manage neuropathic pain; however, these are frequently accompanied by undesirable side effects. Transcutaneous electrical nerve stimulation (TENS) is a safe and non-invasive intervention that has been used to alleviate different types of pain in the clinic, but it is unclear whether TENS can improve chronic neuropathic pain in the upper limb. Thus, the aim of this study was to investigate the effects of a single trial of TENS on chronic neuropathic pain following median nerve injury. Male rats weighing 200-250 g received median nerve-ligation of the right forearm, while the control group received only skin-incision without nerve-ligation. Neuropathic painbehaviors, including mechanical, cold, and thermal allodynia, were measured for 4 weeks. After the development of chronic neuropathic pain, TENS (100 Hz, 200 µs, sub-motor threshold) or placebo-TENS (sham stimulation) was applied for 20 min to the ipsilateral or contralateral side. Neuropathic pain behavior was assessed before and after intervention. Median nerve-ligation significantly induced and maintained neuropathic pain in the ipsilateral side. TENS application to the ipsilateral side effectively attenuated the three forms of chronic neuropathic pain in the ipsilateral side compared to sham-treated rats (peripheral and central effects), while TENS application to contralateral side only reduced mechanical allodynia in the ipsilateral side (central effect). Our findings demonstrate that TENS can alleviate chronic neuropathic pain following median nerve injury.

Late administration of high-frequency electrical stimulation increases nerve regeneration without aggravating neuropathic pain in a nerve crush injury

“…Percutaneous electrical stimulation was shown to alleviate pain in cases of musculoskeletal pain, arthritis pain, low back pain, neuropathic pain, and post-operative pain [ 22 , 23 , 29 , 30 ]. Low-frequency electrical stimulation induced analgesia by inhibiting pain transmission through the recruitment of the descending inhibitory system; however, high-frequency (80–100 Hz) stimulation activated the gate control by stimulation A-beta fibers [ 31 ].There were various inconsistencies amongst previous studies with respect to the therapeutic effect according to the frequencies tested [ 32 ].…”

“…Dorsal root ganglia cells were dissected from embryonic Sprague–Dawley rat at the embryonic days 14–15 according to previous report [ 20 , 22 , 23 ]. The DRGs were incubated with 0.25% trypsin at 37 °C for 15 min and were dissociated, washed and re-suspended with Neurobasal medium containing 2% B27 (sigma, Inc.), 0.3% l -glutamine and 100 ng/ml nerve growth factor.…”

<p>Remote Analgesic Effects Of Conventional Transcutaneous Electrical Nerve Stimulation: A Scientific And Clinical Review With A Focus On Chronic Pain</p>

“…Cho et al studied the analgesic effects of conventional TENS in a rat chronic neuropathic pain model created by ligation of the median nerve. 104 Conventional TENS was applied for 20 minutes ipsilaterally or contralaterally to the nerve injury. Ipsilateral TENS application reduced mechanical, cold, and thermal allodynia compared to sham-treated rats.…”

Effects of transcutaneous electrical nerve stimulation on pain in patients with spinal cord injury: a randomized controlled trial

“…Many studies have shown that TENS is effective for a wide variety of pain, e.g. cancer pain 5 ) , neuropathic pain 6 ) , and low back pain 7 ) .…”