Effect of pulsed radiofrequency on spinal ATP-P2X4-NLRP3 signaling pathway in rats with neuropathic pain

Abstract

Objective To evaluate the effect of pulsed radiofrequency(PRF)on spinal adenosine triphosphate(ATP)-P2X4-NLRP3 signaling pathway in rats with neuropathic pain. Methods Forty healthy clean-grade adult male Sprague-Dawley rats, aged 2-3 months, weighing 220-260 g, were divided into 4 groups(n=10 each)using a random number table method: sham operation group(group S), neuropathic pain group(group NP), sham PRF group(group SPRF)and PRF group.Neuropathic pain was induced by chronic constriction injury to the left sciatic nerve of anesthetized rats.Rats received PRF treatment on 7th day after establishing the model in group PRF.The mechanical paw withdrawal threshold(MWT)and thermal paw withdrawal latency(TWL)were measured before establishing the model(T0)and at 3, 7, 10, 14, 21 and 28 days after establishing the model(T1-6). The rats were then sacrificed and the spinal cord was removed for determination of P2X4 and NLRP3 expression(by Western blot)and interleukin-1beta(IL-1β), IL-2, IL-6 and tumor necrosis factor-alpha(TNF-α)contents(by enzyme-linked immunosorbent assay). Results Compared with group S, the MWT and TWL were significantly decreased at T1-6, the expression of P2X4 and NLRP3 was up-regulated, and the contents of IL-1β, IL-2, IL-6 and TNF-α were increased in NP, SPRF and PRF groups(P<0.05). Compared with group NP and group SPRF, the MWT and MWT were significantly increased at T3-6, the expression of P2X4 and NLRP3 was down-regulated, and the contents of IL-1β, IL-2, IL-6 and TNF-α were decreased in group PRF(P<0.05). Conclusion The mechanism by which PRF alleviates neuropathic pain is related to inhibiting ATP-P2X4-NLRP3 signaling pathway in rats. Key words: Catheter ablation; Neuralgia; Spinal cord; Receptors, cell surface; NLR family, pyrin domain-containing 3 protein