Abstract: Objective To evaluate the effect of pulsed radiofrequency (PR) of dorsal root ganglion (DRG) on the expression of astrocyte marker GFAP and microglia maker OX42 in spinal cord of rats with inflammatory pain. Methods Thirty-two male SD rats were randomly divided into 4 groups (n=8 for each group), including control group (group C), inflammation pain group (group IP), pulsed radiofrequency group (group PR) and inflammation pain combined with pulsed radiofrequency group (group IP+PR). Pulsed radiofrequency surgery on L4-L5 DRGs was performed at 4 days after IP model. Mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured before (d0) and 1, 3, 5, 7 days (d1, d3, d5, d7) after IP model. The rats were sacrificed after the last measurement of pain threshold, and protein expressions of GFAP and OX42 in the L4-L6 spinal segment in four groups of rats were detected by Western blot assay. Results Compared with group C and group PR, MWT and TWL were decreased in different time points after IP model in group IP and group IP+PR (P＜0.05). Compared with group IP, MWT and TWL were increased in group IP+PR after pulsed radiofrequency (P＜0.05). The protein expressions of GFAP and OX42 were up-regulated in group IP and group IP+PR compared with those of group C and group PR (P＜0.05). Compared with group IP, GFAP and OX42 protein expressions decreased in group IP+PR (P＜0.05). Conclusion The pulsed radiofrequency of DRGs can alleviate the hyperalgesia and inhibit activation of astrocyte and microglia in spinal cord of inflammatory pain rats.

Key words: ganglia, spinal, neurons, inflammation, neuralgia, astrocyte, microglia