Effects of pulsed radiofrequency application to dorsal root ganglia on expression of IRF8 in spinal cord and BDNF in nucleus accumbens of rats with neuropathic pain

Abstract

Objective To evaluate the effects of pulsed radiofrequency(PRF)application to dorsal root ganglia on the expression of interferon regulatory factor 8(IRF8)in the spinal cord and brain-derived neurotrophic factor(BDNF)protein in the nucleus accumbens of rats with neuropathic pain(NP). Methods Forty healthy pathogen-free male Wistar rats, weighing 180-200 g, aged 2 months, were divided into 4 groups(n=10 each)using a random number table: sham operation group(group Sham), group NP, sham PRF group(group SPRF)and PRF group.NP was induced by chronic constriction injury(CCI)to the left sciatic nerve of anesthetized rats.The mechanical paw withdrawal threshold(MWT)was measured before CCI and at 3, 7, 10, 14, 21, 28, 35 and 42 days after CCI.Sucrose preference test and forced-swim test were performed at 42 days after CCI for determination of the expression of IRF8 in the spinal cord and BDNF in the nucleus accumbens by Western blot. Results Compared with group Sham, the MWT at each time point after CCI and rate of preference for sucrose were significantly decreased, the duration of immobility in forced-swim test was prolonged, and the expression of IRF8 and BDNF was up-regulated in NP, SPRF and PRF groups(P 0.05). Conclusion The mechanism by which PRF application to dorsal root ganglia alleviates NP and depressive-like behaviors is probably related to down-regulation of the expression of IRF8 in the spinal cord and BDNF in the nucleus accumbens of rats. Key words: Catheter ablation; Ganglia, spinal; Neuralgia; Interferon regulatory factors; Brain-derived neurotrophic factor; Spinal cord; Nucleus accumbens