Changes in the gene expression in mouse astrocytes induced by pulsed radiofrequency: A preliminary study

Glial cells, both astrocytes and microglia, play important roles in the induction and maintenance of neuroinflammation resulting in neuropathic pain. Pulsed radiofrequency (PRF) is applied to various nerves for the treatment of pain, although the molecular mechanism underlying its effects is still unclear. We herein investigated the genomic effects of PRF on a mouse cultured astrocyte cell line. PRF was applied to the cultured astrocytes in 20-msec pulses of 480 kHz every 500 msec, delivered at the rate of 2 Hz, for 30 min. PRF increased the expression of 2,431 genes and decreased that of 209 genes. Among these genes, 435 genes were upregulated >10-fold and 89 genes >30-fold, while no genes showed a 10-fold decrease in expression. A gene ontology analysis using the list of >10-fold upregulated genes showed that PRF treatment activated immune responses. A pathway analysis using the Kyoto Encyclopedia of Gene and Genomes with the same list detected seven pathways related to neuropathic pain. These findings suggest that PRF improves neuropathic pain via neuroimmunomodulation.