The Effect And The Mechanism Of The Pulse Radiofrequency Applied Proximal To Dorsal Root Ganglia In Pain Behavior Of CCI Rats

Objective:The study aims to investigate the effect of pulse radio frequency(PRF)applied proximal to dorsal root ganglion on pain behavior of the SD rats receiving chronic constriction injury(CCI).The ?-catenin expression in the spinal dorsal horn and the levels of IL-1? and TNF-? in the blood and the sciatic nerve have also been investigated.Methods:The rats were divided into four groups according to random number table:animals those sciatic nerve was separated without ligation(sham surgery)and received sham PRF(the electrode was placed proximal to DRG without stimuli)were in group Sham+Sham;animals those received sham surgery and the PRF was applied proximal to DRG were in group Sham+PRF;animals those sciatic nerve was ligated(CCI)and received sham PRF were in group CCI+Sham;animals those sciatic nerve was ligated(CCI)and received PRF treatment were in group CCI+PRF;n=10 for each group.In the 4th day after CCI,PRF was implemented with pulse width 20 ms,2 Hz frequency,.40v,pulse duration of 120s,The mechanical withdrawal threshold(MWT)and thermal withdrawal latency(TWL)were detected on the day before CCI model(D.1),the 1st day(D1),the 3rd day(D3),the 5th day(D5),the 7th day(D7),the 9th day(D9),the 11th day(D11),the 13th day(D13)and the 14th day(D14)after CCI.The expression of ?-catenin in dorsal horn of spinal cord was measured by Western-blot ant the levels of IL-1? and TNF-a in serum and the sciatic nerves was measured by ELISA method.Results:The MWT of CCI+PRF group on D5,D7,D9,D11,D13 and D,4 was higher than that of CCI+Sham group,which was statistically significant(p<0.05).The TWL of CCI+PRF group on D7,D9,D11,D13 and D14 was significantly longer than that in CCI+Sham group,which was statistically significant(p<0.05).The expression level of?-catenin protein in the lumbar spinal dorsal horn of CCI+PRF group was lower than that in CCI+Sham group on D14,which was statistically significant(p<0.05).On D14,serum levels of IL-1? and TNF-? of CCI+PRF group were lower than in CCI+Sham group,which was statistically significant(p<0.05).TNF-? concentration in the injury sciatic nerve of CCI+PRF group was lower than that in CCI+Sham group on D14 which was statistically significant(p<0.05).Conclusion:Pulse radiofrequency applied proximal to dorsal root ganglion improves mechanical withdrawal threshold and thermal withdrawal latency of CCI rats,downregulates the expression of ?-catenin in spinal dorsal horn of CCI rats and reduces the levels of IL-1? and TNF-? in serum.Pulse radiofrequency could alleviate the neuropathic pain,and decreasing the inflammation factor and inhibiting Wnt/?-catenin pathway maybe contribute to its underlying mechanism.