The effect of pulsed radiofrequency on dorsal root ganglion on the met-enkephalin and substance P levels in the spinal cord in spinal nerve injury rats

Objective Applied pulsed radiofrequency on dorsal root ganglion of spared nerve injury(SNI) rats then examined the changes of met-enkephalin(M-ENK) and substance P(SP) levels in the spinal cord.The aim of this study is to find the possible mechanism of pulsed radiofrequency in the treatment of neuropathic pain and provide evidence for clinical applying.Methods Forty-eight male SD rats were randomly divided into six groups:the normal group(n=8),the SNI group(n=8),the 2 h after sham operation group(n=8),the 2 h after pulsed radiofrequency group(n=8),the 24 h after sham operation group(n=8),and the 24 h after pulsed radiofrequency group(n=8).The M-ENK and SP levels in spinal cord were examined by radioimmunoassay 2 h or 24 h after pulsed radiofrequency or sham operation.Results Two hours after the pulsed radiofrequency,the M-ENK levels decreased significantly.However,24 h after the pulsed radiofrequency,the M-ENK levels significantly increased.The SP level increased significantly after the SNI procedure,and were examined further increase at the 2 h and 24 h after pulsed radiofrequency.Conclusions This study demonstrated that applying pulsed radiofrequency can increase the endogenous M-ENK and SP levels in spinal cord in rat SNI model,this was involved in the effect of pulsed radiofrequency on neuropathic pain therapy.