Prolonged-duration pulsed radiofrequency is associated with increased neuronal damage without further antiallodynic effects in neuropathic pain model rats
Authors Arakawa K, Kaku R, Kurita M, Matsuoka Y, Morimatsu H
Received 13 March 2018
Accepted for publication 20 August 2018
Published 30 October 2018 Volume 2018:11 Pages 2645—2651
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 3
Editor who approved publication: Dr Erica Wegrzyn
Kyosuke Arakawa, Ryuji Kaku, Masako Kurita, Yoshikazu Matsuoka, Hiroshi Morimatsu
Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama City, Okayama, Japan
Aim of investigation: Pulsed radiofrequency (PRF) is a safe and effective approach for treating neuropathic pain. However, the optimal treatment conditions and analgesic mechanisms of PRF remain unclear. The aim of our study was to assess the beneficial and adverse effects of prolonged-duration PRF and the analgesic mechanisms of PRF treatment with neuropathic pain rats.
Methods: Male Sprague Dawley rats received L5 spinal nerve ligation (SNL) for developing neuropathic pain. Fourteen days after L5 SNL surgery, they were divided into three groups according to duration of PRF current for 6 minutes, 12 minutes, and none. PRF current was delivered via direct visualization adjacent to the L5 dorsal root ganglion (DRG). Pain behavior was evaluated every week after L5 SNL surgery, until day 28. Seven days after PRF treatment, L5 DRG tissue was harvested to detect levels of activating translation factor 3 (ATF3; a marker of neuronal damage) and hyperpolarization-activated cyclic nucleotide (HCN)-gated cation channels (key factors in neuropathic pain) using quantitative PCR.
Results: Before PRF application, withdrawal thresholds were significantly lower than at baseline and did not differ significantly between the three groups. After PRF application, withdrawal thresholds in the PRF6 and PRF12 groups were significantly increased compared to those in the sham group. However, those in the PRF6 and PRF12 groups did not differ significantly. The expression level of ATF3 mRNA in the PRF12 group was significantly higher than that in the sham group (P<0.01), but the expression of HCN1 and HCN2 channels did not differ significantly between the three groups.
Conclusion: Prolonged PRF exposure, from 6 to 12 minutes, was not only ineffective but also associated with increased neuronal damage. These findings do not support prolonged PRF exposure as a helpful treatment for neuropathic pain. In this study, the involvement of HCN channels in the antiallodynic effects of PRF was uncertain.
Keywords: pulsed radiofrequency, neuropathic pain, dorsal root ganglion, ATF3, HCN channels
This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms.Download Article [PDF] View Full Text [HTML][Machine readable]