Effect of application of pulsed radiofrequency to dorsal root ganglia on activation of spinal astrocytes in a rat model of neuropathic pain

Objective To evaluate the effect of application of pulsed radiofrequency to dorsal root ganglia on activation of spinal astrocytes in a rat model of neuropathic pain (NP). Methods Eighty male Sprague-Dawley rats, aged 6-8 weeks, weighing 200-250 g, were divided into 4 groups (n=20 each) using a random number table method: sham operation group (group Sham), group NP, pulsed radiofrequency group (PRF group) and sham pulsed radiofrequency group (group SPRF). NP was induced by chronic constriction injury (CCI). The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before CCI and 1, 7, 14 and 21 days after CCI.Four rats were sacrificed at 1 day before CCI and 14 and 21 days after CCI, and the L4-6 segments of the spinal cord were harvested to detect the expression of glial fibrillary acidic protein (GFAP) and interleukin-1beta (IL-1β) by Western blot. Results Compared with group Sham, the MWT was significantly decreased and the TWL was shortened at each time point after CCI, and the expression of GFAP and IL-1β was up-regulated at 14 and 21 days after CCI in NP, PRF and SPRF groups (P 0.05). Conclusion The mechanism by which pulsed radiofrequency reduces NP is probably related to inhibiting spinal astrocyte activation in rats. Key words: Catheter ablation; Ganglia, spinal; Neuralgia; Spinal cord; Astrocytes