Dai Zhisen, Xu Xueru, Chen Yanqin, Lin Chun, Lin Fan, Liu Rongguo
Department of Pain Management, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, China.
Laboratory of Pain Research, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.
Neuromodulation. 2022 Oct;25(7):980-988. doi: 10.1111/ner.13527. Epub 2022 Jun 14.
To investigate the analgesic effect of high-voltage pulsed radiofrequency (HV-PRF) on the dorsal root ganglion (DRG) for neuropathic pain induced by spared nerve injury (SNI) in rats, especially the influence of this treatment on the DRG ultrastructure and voltage-gated sodium channel 1.7 (Nav1.7) level in the DRG.
One hundred fifty adult male Sprague-Dawley rats were randomly divided into five groups: Sham, SNI, Free-PRF, standard-voltage PRF (SV-PRF), and HV-PRF. The 45V-PRF and 85V-PRF procedures applied to the left L5 DRG were performed in SV-PRF group and the HV-PRF group, respectively, on day 7 after SNI, whereas no PRF was concurrently delivered in Free-PRF group. The paw mechanical withdrawal threshold (PMWT) was detected before SNI (baseline) and on days 1, 3, 7, 8, 10, 14, and 21. The changes of left L5 DRG ultrastructure were analyzed with transmission electron microscopy on days 14 and 21. The expression levels of Nav1.7 in left L5 DRG were detected by immunofluorescence and Western blot.
Compared with the Free-PRF group, PMWT in the SV-PRF group and HV-PRF group were both significantly increased after PRF (all p < 0.05). Meanwhile, the PMWT was significantly higher in the HV-PRF group than that in the SV-PRF group on days 14 and 21 (all p < 0.05). There were statistically significant differences between the SV-PRF and Free-PRF groups (p < 0.05). Similarly, statistically significant difference was found between the HV-PRF and Free-PRF groups (p < 0.05). Especially, comparison of the SV-PRF group and the HV-PRF group revealed statistically significant difference (p < 0.05). The Nav1.7 levels were significantly downregulated in the SV-PRF group and HV-PRF groups compared to that in the Free-PRF group (all p < 0.01). A significantly lower Nav1.7 level was also found in the HV-PRF group compared to that in the SV-PRF group (p < 0.05).
The HV-PRF produces a better analgesic effect than SV-PRF applied to the DRG in SNI rats. The underlying mechanisms may be associated with improving the histopathological prognosis and the downregulation of Nav1.7 levels in the DRG.
研究高压脉冲射频（HV-PRF）对大鼠 spared 神经损伤（SNI）所致神经性疼痛的背根神经节（DRG）的镇痛作用，尤其是该治疗对 DRG 超微结构以及 DRG 中电压门控钠通道 1.7（Nav1.7）水平的影响。
150 只成年雄性 Sprague-Dawley 大鼠随机分为五组：假手术组、SNI 组、自由射频组、标准电压射频（SV-PRF）组和 HV-PRF 组。SNI 术后第 7 天，SV-PRF 组和 HV-PRF 组分别对左侧 L5 DRG 进行 45V-PRF 和 85V-PRF 操作，而自由射频组未同时进行射频治疗。在 SNI 前（基线）以及术后第 1、3、7、8、10、14 和 21 天检测 paw 机械性缩足阈值（PMWT）。在术后第 14 天和 21 天用透射电子显微镜分析左侧 L5 DRG 的超微结构变化。通过免疫荧光和蛋白质印迹法检测左侧 L5 DRG 中 Nav1.7 的表达水平。
与自由射频组相比，SV-PRF 组和 HV-PRF 组在进行射频治疗后 PMWT 均显著升高（所有 p < 0.05）。同时，在术后第 14 天和 21 天，HV-PRF 组的 PMWT 显著高于 SV-PRF 组（所有 p < 0.05）。SV-PRF 组与自由射频组之间存在统计学显著差异（p < 0.05）。同样，HV-PRF 组与自由射频组之间也存在统计学显著差异（p < 0.05）。特别是，SV-PRF 组与 HV-PRF 组比较显示存在统计学显著差异（p < 0.05）。与自由射频组相比，SV-PRF 组和 HV-PRF 组中 Nav1.7 水平均显著下调（所有 p < 0.01）。与 SV-PRF 组相比，HV-PRF 组中 Nav1.7 水平也显著降低（p < 0.05）。
在 SNI 大鼠中，应用于 DRG 的 HV-PRF 产生的镇痛效果优于 SV-PRF。其潜在机制可能与改善组织病理学预后以及下调 DRG 中 Nav1.7 水平有关。
