Abstract: Objective To observe the hindpaw withdrawal threshold (HWT), and the ultrastructure and expression of glia cell line-derived neurotrophic factor (GDNF) in sciatic nerve (SN) in chronic constriction injury (CCI) rats after pulsed radiofrequency (PRF). Methods 30 Sprague-Dawley rats were divided into sham modeling-sham treating (SS) group, CCI-Sham treating (CS) group and CCI-PRF (CP) group. The right SNs of the rats in the CS and CP groups were ligated, and it was separated without ligation in the SS group. The CP group accepted PRF at the ligation 14 days after modeling, while the electrodes were placed without electricity in the SS and CS groups. Their HWT was measured before and 1, 7, 14 days after modeling, and 1, 7, 14 days after treatment. The right SN of ligation was observed under electron microscope 14 days after treatment, meanwhile, the GDNF expression was determined with enzyme-linked immunosorbent assay (ELISA). Results HWT was significantly shorter in the CS and CP groups than in the SS group after modeling, and it increased in the CP group 14 days after treatment compared with that of the CS group (P<0.01). The degeneration of SN significantly improved in the CP group compared with the CS group, while the expression of GDNF increased compared with that in the CS and SS groups (P<0.01). Conclusion PRF could relieve the CCI-induced neuropathic pain by upregulating the GDNF expression in the SN to prevent the SN from injury.

Key words: neuropathic pain, sciatic nerve, pulsed radiofrequence, chronic constriction injury, glial cell line-derived neurotrophic factor, rats